You searched for subject:(gel dosimetry).
Showing records 1 – 30 of
61 total matches.
◁ [1] [2] [3] ▶
Queen Mary, University of London
1.
Poxon, J. E.
Translating 3D gel dosimetry research into clinical routine use in radiotherapy.
Degree: PhD, 2019, Queen Mary, University of London
URL: http://qmro.qmul.ac.uk/xmlui/handle/123456789/55452 
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.786348
► Radiotherapy involves the treatment of tumours with ionising radiation. Technological advances have improved the ability to conform dose distributions to tumours in three dimensions (3D)…
(more)
▼ Radiotherapy involves the treatment of tumours with ionising radiation. Technological advances have improved the ability to conform dose distributions to tumours in three dimensions (3D) and thereby reduce morbidity. However, sophisticated measurement devices are required to verify these complex distributions and ensure their accuracy. Radiation-sensitive gels, including polymer and Fricke gels, are a potential solution to this 3D dosimetry problem. Scanning these detectors using imaging methods such as magnetic resonance imaging (MRI) provides quantifiable images of dose distribution. Despite research efforts, 3D gel dosimetry has not yet been implemented as a routine dosimetry tool in clinical radiotherapy. This thesis aims to investigate the implementation of Fricke gel detectors within a clinical radiotherapy department. The existing literature was reviewed to establish what evidence already existed on the dosimetric accuracy of Fricke gel detectors. This review highlighted gaps for many important dosimetric characteristics and a lack of a systematic approach to the testing of these detectors. Basic dosimetric characteristics were then investigated using test tube Fricke gel samples and an MR spectrometer. These experiments showed an excellent basic precision over a dose range of 3 to 20Gy. However, detectors need to be scanned within a certain time of irradiation to avoid signal drift. There was no evidence of any dependence of response on dose rate, energy or fractionation. Larger volume detector samples were analysed using a 3T MRI scanner. Detector response was homogeneous and did not vary with volume. Post-irradiation blurring of the measured distribution due to ferric ion diffusion was within acceptable limits if detectors were scanned within 2 hours following irradiation for typical clinical dose gradients. Finally, large volume Fricke gel detectors were used to measure complex VMAT stereotactic plans, describing the integrated dose distribution with sufficient accuracy and demonstrating clear potential to be applied to our clinical practice.
Subjects/Keywords: Radiation; dosimetry; Fricke gel detectors
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Poxon, J. E. (2019). Translating 3D gel dosimetry research into clinical routine use in radiotherapy. (Doctoral Dissertation). Queen Mary, University of London. Retrieved from http://qmro.qmul.ac.uk/xmlui/handle/123456789/55452 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.786348
Chicago Manual of Style (16th Edition):
Poxon, J E. “Translating 3D gel dosimetry research into clinical routine use in radiotherapy.” 2019. Doctoral Dissertation, Queen Mary, University of London. Accessed April 11, 2021.
http://qmro.qmul.ac.uk/xmlui/handle/123456789/55452 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.786348.
MLA Handbook (7th Edition):
Poxon, J E. “Translating 3D gel dosimetry research into clinical routine use in radiotherapy.” 2019. Web. 11 Apr 2021.
Vancouver:
Poxon JE. Translating 3D gel dosimetry research into clinical routine use in radiotherapy. [Internet] [Doctoral dissertation]. Queen Mary, University of London; 2019. [cited 2021 Apr 11].
Available from: http://qmro.qmul.ac.uk/xmlui/handle/123456789/55452 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.786348.
Council of Science Editors:
Poxon JE. Translating 3D gel dosimetry research into clinical routine use in radiotherapy. [Doctoral Dissertation]. Queen Mary, University of London; 2019. Available from: http://qmro.qmul.ac.uk/xmlui/handle/123456789/55452 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.786348
Queens University
2.
Chain, Jonathan.
Recipe Improvement and Mathematical Modelling of Polymer Gel Dosimeters
.
Degree: Chemical Engineering, 2011, Queens University
URL: http://hdl.handle.net/1974/6307
► A mathematical model for polymer gel dosimeters was extended to simulate the effects of radiation depth doses of various radiation beams on the mass of…
(more)
▼ A mathematical model for polymer gel dosimeters was extended to simulate the effects of radiation depth doses of various radiation beams on the mass of polymer formed. The influences of monomer diffusion and temperature variation were investigated and predicted by the model. Simulation results indicate that both diffusion and temperature effects are most noticeable at the depth of maximum dose. Diffusion effects are larger for steep depth-dose curves with large dose gradients, while temperature effects are larger for extensive depth-dose curves that deliver high doses of radiation to a greater depth. Based on simulation results, involving a maximum dose of 5 Gy, the amount of additional polymer formed due to diffusion is small, ranging from 0.1 % for 15 MV x-ray photons to 2.6 % for Co60 γ-radiation. This small amount of additional polymer should not cause significant problems for the accuracy of depth-dose calibration curves, particularly if the depth of maximum dose is avoided. Inaccuracies caused by temperature effects are expected to be smaller than those caused by diffusion.
Experimental studies were undertaken to improve the radiation dose response using x-ray Computed Tomography (CT). A new polymer gel dosimeter recipe with enhanced dose response was achieved by using a large quantity of N-isopropyl acrylamide (NIPAM) (15 wt%) to help dissolve the N,N’-methylene bisacrylamide (Bis) crosslinker. The solubility of Bis was substantially increased, allowing for large quantities of dissolved NIPAM and Bis in the system. The new dosimeter exhibits an enhanced dose sensitivity and dose resolution for x-ray CT imaging, which holds promise for clinical applications. The dose resolution of approximately 0.1 Gy, for up to absorbed doses of 50 Gy, for the new recipe is superior to that for previous dosimeter formulations developed for x-ray CT.
Subjects/Keywords: Modelling
;
Polymer gel dosimetry
;
Radiation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Chain, J. (2011). Recipe Improvement and Mathematical Modelling of Polymer Gel Dosimeters
. (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/6307
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Chain, Jonathan. “Recipe Improvement and Mathematical Modelling of Polymer Gel Dosimeters
.” 2011. Thesis, Queens University. Accessed April 11, 2021.
http://hdl.handle.net/1974/6307.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Chain, Jonathan. “Recipe Improvement and Mathematical Modelling of Polymer Gel Dosimeters
.” 2011. Web. 11 Apr 2021.
Vancouver:
Chain J. Recipe Improvement and Mathematical Modelling of Polymer Gel Dosimeters
. [Internet] [Thesis]. Queens University; 2011. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/1974/6307.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Chain J. Recipe Improvement and Mathematical Modelling of Polymer Gel Dosimeters
. [Thesis]. Queens University; 2011. Available from: http://hdl.handle.net/1974/6307
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Queensland University of Technology
3.
Smith, Shaun T.
Development of gel dosimetry for radiotherapy.
Degree: 2017, Queensland University of Technology
URL: https://eprints.qut.edu.au/102759/
► Gel dosimeters have the potential to track radiation beams, improving safety and treatment effectiveness for radiotherapy patients, however despite extensive research over the last three…
(more)
▼ Gel dosimeters have the potential to track radiation beams, improving safety and treatment effectiveness for radiotherapy patients, however despite extensive research over the last three decades, gel dosimeters have yet to achieve widespread clinical acceptance. In this research, a new version of the ‘Fricke’ gel dosimeter was developed which is more clinically viable. The method performs chemical manipulations on the gel ingredients to eliminate the blurring effect of dose information, which is their primary drawback.
Subjects/Keywords: gel dosimetry; radiotherapy; dose verification; 3D dosimetry; diffusion; chemical dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Smith, S. T. (2017). Development of gel dosimetry for radiotherapy. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/102759/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Smith, Shaun T. “Development of gel dosimetry for radiotherapy.” 2017. Thesis, Queensland University of Technology. Accessed April 11, 2021.
https://eprints.qut.edu.au/102759/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Smith, Shaun T. “Development of gel dosimetry for radiotherapy.” 2017. Web. 11 Apr 2021.
Vancouver:
Smith ST. Development of gel dosimetry for radiotherapy. [Internet] [Thesis]. Queensland University of Technology; 2017. [cited 2021 Apr 11].
Available from: https://eprints.qut.edu.au/102759/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Smith ST. Development of gel dosimetry for radiotherapy. [Thesis]. Queensland University of Technology; 2017. Available from: https://eprints.qut.edu.au/102759/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
4.
Thiago Dias Resende.
Um estudo para otimização da formulação do dosímetro gel MAGIC-f e avaliação da sua reutilização.
Degree: 2017, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-07072017-123749/
► A radioterapia é um procedimento que utiliza radiação ionizante de alta energia direcionado ao tumor, para destruir suas células. O objetivo é provocar o maior…
(more)
▼ A radioterapia é um procedimento que utiliza radiação ionizante de alta energia direcionado ao tumor, para destruir suas células. O objetivo é provocar o maior dano nas células tumorais enquanto se poupa o tecido sadio ao redor, para maximizar este resultado. Devido a alta complexidade dos feixes usados nestes tratamentos, um dosímetro tridimensional é desejado para garantir que a dose esteja sendo entregue da forma como foi planejada, sendo a dosimetria gel polimérica com leitura da dose em Imagens de Ressonância Magnética Nuclear (IRMN), uma opção para esta medida. Esse trabalho utiliza o dosímetro gel polimérico MAGIC-f como referência e tem como objetivo otimizar sua formulação, substituindo inicialmente os seus agentes antioxidantes (sulfato de cobre e ácido ascórbico) por um antioxidante mais potente, o cloreto de tetrakishidroximetilfosfônio (THPC), e, em seguida, variar as concentrações dos demais componentes do dosímetro a fim de obter a
menor concentração de cada um deles que resulte em um dosímetro com sensibilidade adequada para uso em radioterapia.Foram feitas análises sobre a estabilidade térmica do dosímetro com THPC e estudos sobre as concentrações ideais de THPC (2mM, 5mM, 8mM, 10mM ou 20mM); Ácido Metacrílico (2%, 2,5%, 3%, 3,5% ou 4%); Gelatina (4%, 6%, 8% ou 10%). Após todas as modificações, a formulação otimizada contendo 88,96% Água MiliQ; 3% Ácido Metacrílico; 8% Gelatina; 0,04% THPC (5mM de concentração), apresentou uma sensibilidade próxima a 1,03 Gy-1s-1 e um ponto de fusão de aproximadamente 50C, utilizando as menores quantidades possíveis dos reagentes químicos e a sequência de leitura das IRMN implementada para esta dosimetria. O dosímetro otimizado obtido teve uma redução de 40% no seu custo, em comparação com o dosímetro MAGIC-f, e uma resolução de dose de 0,18 Gy. Obteve linearidade de resposta a dosede 0 a 10 Gy. Uma variação máxima na sensibilidade do dosímetro de 8,5% foi encontrada ao se
variar a taxa de dose de 300 500 cGy/min.Também foi avaliada a integridade da distribuição de dose para esse dosímetro através da avaliação de uma irradiação com meio campo blindado. E, sua a maior variação em um teste de repetitividade foi de 15%. Um outro objetivo deste trabalho foi o desenvolvimento de uma metodologia para a reutilização do dosímetro gel, sendo que um dosímetro previamente irradiado com uma dose de 2Gy foi reutilizado após seu derretimento a 50C em um forno com controle digital de temperatura, seguido por uma nova gelificação.Para garantir sua resposta, foi necessária a readição de agentes antioxidantes à formulação reutilizada. Dessa forma, para o gel MAGAT com 1mM de THPC foi obtida uma sensibilidade 30% menor que a original para o dosímetro reutilizado e 15% para o mesmo dosímetro, com 2mM de THPC
Radiotherapy is a procedure that uses high energy ionizing radiation directed to the tumor to destroy its cells. The objective is to obtain tumoral cells more
damaged avoiding the healthy cells around it and increase this result. Due to the high complexity of the energy…
Advisors/Committee Members: Juliana Fernandes Pavoni, Oswaldo Baffa Filho, Alexandre Colello Bruno, Mirko Salomón Alva Sánchez.
Subjects/Keywords: Dosimetria gel; MAGAT; MAGIC-f; Radioterapia; Reciclagem dosímetro gel; THPC; Gel dosimetry; Gel-dosimetry recycling; MAGAT; MAGIC-f; Radiotherapy; THPC
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Resende, T. D. (2017). Um estudo para otimização da formulação do dosímetro gel MAGIC-f e avaliação da sua reutilização. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-07072017-123749/
Chicago Manual of Style (16th Edition):
Resende, Thiago Dias. “Um estudo para otimização da formulação do dosímetro gel MAGIC-f e avaliação da sua reutilização.” 2017. Masters Thesis, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-07072017-123749/.
MLA Handbook (7th Edition):
Resende, Thiago Dias. “Um estudo para otimização da formulação do dosímetro gel MAGIC-f e avaliação da sua reutilização.” 2017. Web. 11 Apr 2021.
Vancouver:
Resende TD. Um estudo para otimização da formulação do dosímetro gel MAGIC-f e avaliação da sua reutilização. [Internet] [Masters thesis]. University of São Paulo; 2017. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-07072017-123749/.
Council of Science Editors:
Resende TD. Um estudo para otimização da formulação do dosímetro gel MAGIC-f e avaliação da sua reutilização. [Masters Thesis]. University of São Paulo; 2017. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-07072017-123749/
University of Victoria
5.
Maynard, Evan David.
Applications of x-ray computed tomography polymer gel dosimetry.
Degree: Department of Physics and Astronomy, 2018, University of Victoria
URL: https://dspace.library.uvic.ca//handle/1828/10461
► Radiation therapy, one of the most common forms of cancer treatment, is continually evolving with the introduction of new technology, more complex treatments and more…
(more)
▼ Radiation therapy, one of the most common forms of cancer treatment, is continually evolving with the introduction of new technology, more complex treatments and more advanced radiation dose calculations. To ensure the effectiveness and safety of modern radiation therapy, dose measurement tools must improve to accommodate these advances. X-ray computed tomography (CT) polymer
gel dosimetry is a unique type of dosimeter that has many advantages and the potential to address some of the challenges in the verification of dose delivery and calculation in radiation therapy. This dissertation investigates the advancement of an x-ray CT polymer
gel dosimetry system for use in clinical applications and in particular for deformable dose verification.
The first part of this work consists of a reproducibility study of an established x-ray CT polymer
gel dosimetry system in an effort to determine the accuracy and precision of dose measurements made with this system and the feasibility of interbatch and generic calibration.
Gel measurements were found to have excellent agreement with Monte Carlo dose calculation when using a generic calibration curve. The excellent dosimetric and spatial accuracy established in this study suggest that this
dosimetry system is ideally suited for the measurement of high-dose fractionation treatments such as stereotactic radiosurgery (SRS) or stereotactic body radiation therapy (SBRT). The second stage was the development and characterization of the first deformable x-ray CT polymer
gel dosimetry system. This study established the setup reproducibility, deformation characteristics and dose response of the new deformable system. The dose response was found to be similar to that of the non-deformable system with similar dosimetric and spatial accuracy when compared to Monte Carlo dose calculation. The system was also found to have sub-millimetre setup reproducibility and the deformable dosimeter was found to reproducibly deform and relax for external compression of up to 30 mm and over 100 consecutive compressions. This work established several important characteristics of the new deformable
dosimetry system and it shows excellent potential for use in the evaluation of deformable dose accumulation algorithms.
The final component of this dissertation was the use of the newly developed deformable
dosimetry system in the evaluation of a novel deformable dose accumulation algorithm, defDOSXYZ.
Gel measurements and defDOSXYZ showed excellent agreement in the case of a static control case and this set a benchmark for deformable dose measurements. Measurements of deformed dose by the
gel dosimeter showed significant disagreement with dose deformed by defDOSXYZ and the dosimetric differences were well outside the uncertainties established in the first two studies of this dissertation. The results from this study provided some insight into potential avenues of improvement for both the deformable dose calculation and deformable dose measurements. These results were also the first example of deforming dose…
Advisors/Committee Members: Jirasek, Andrew (supervisor), Hilts, Michelle Louise (supervisor).
Subjects/Keywords: gels; dosimetry; polymer gel dosimetry; radiation dosimetry; deformable dosimetry; dose deformation; x-ray CT; 3D dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Maynard, E. D. (2018). Applications of x-ray computed tomography polymer gel dosimetry. (Thesis). University of Victoria. Retrieved from https://dspace.library.uvic.ca//handle/1828/10461
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Maynard, Evan David. “Applications of x-ray computed tomography polymer gel dosimetry.” 2018. Thesis, University of Victoria. Accessed April 11, 2021.
https://dspace.library.uvic.ca//handle/1828/10461.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Maynard, Evan David. “Applications of x-ray computed tomography polymer gel dosimetry.” 2018. Web. 11 Apr 2021.
Vancouver:
Maynard ED. Applications of x-ray computed tomography polymer gel dosimetry. [Internet] [Thesis]. University of Victoria; 2018. [cited 2021 Apr 11].
Available from: https://dspace.library.uvic.ca//handle/1828/10461.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Maynard ED. Applications of x-ray computed tomography polymer gel dosimetry. [Thesis]. University of Victoria; 2018. Available from: https://dspace.library.uvic.ca//handle/1828/10461
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Queens University
6.
Holmes, Oliver.
Validation of conformal radiotherapy treatments in 3D using polymer gel dosimeters and optical computed tomography
.
Degree: Physics, Engineering Physics and Astronomy, 2008, Queens University
URL: http://hdl.handle.net/1974/1638
► Polymer gel dosimeters are a three dimensional (3D) dosimetry system that may be conveniently applied for verifying highly conformal radiation therapies where standard dosimetry techniques…
(more)
▼ Polymer gel dosimeters are a three dimensional (3D) dosimetry system that may be conveniently applied for verifying highly conformal radiation therapies where standard dosimetry techniques are insufficient. Polymer gel dosimetry with optical computed tomography (OptCT) can be used to measure spatial dose distributions with high resolution. While long experience with MRI has yielded many studies reporting on experiments involving validation of clinical deliveries using polymer gel dosimeters, there are very few studies of this type where OptCT is used. OptCT is a relatively new technique and consequently has not yet been adopted into the clinical environment. As a result, methods and software tools for integrating OptCT measurements into clinical systems are not available. Previous studies from the Medical Physics research group at the Cancer Centre of Southeastern Ontario (CCSEO) and Queen’s University have therefore been limited to simple deliveries and two dimensional (2D) comparisons. In this thesis various software tools and calibration techniques have been developed to allow comparative analysis between OptCT measurements with dose distributions calculated by treatment planning software. Further, a modification of the γ-evaluation (Low et al. 1998) is presented whereby the vector components of γ are used to identify the sources of disagreement between compared dose distributions. Test simulations of the new γ-tool revealed that individual vector components of γ, as well as the resulting vector field can be used to identify certain types of disagreements between dose distributions: especially spatial misalignments caused by geometric misses. The polymer gel dosimetry tools and analysis software were applied to a clinical validation mimicking a prostate conformal treatment with patient setup correction using image guidance. In one experiment greater than 90 % agreement was found between dose distributions in 4%T 50%C NIPAM/Bis dosimeters (Senden et al. 2006) measured with the Vista OptCT unit and dose distributions calculated by Eclipse treatment planning software.
Subjects/Keywords: Radiotherapy
;
Gel Dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Holmes, O. (2008). Validation of conformal radiotherapy treatments in 3D using polymer gel dosimeters and optical computed tomography
. (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/1638
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Holmes, Oliver. “Validation of conformal radiotherapy treatments in 3D using polymer gel dosimeters and optical computed tomography
.” 2008. Thesis, Queens University. Accessed April 11, 2021.
http://hdl.handle.net/1974/1638.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Holmes, Oliver. “Validation of conformal radiotherapy treatments in 3D using polymer gel dosimeters and optical computed tomography
.” 2008. Web. 11 Apr 2021.
Vancouver:
Holmes O. Validation of conformal radiotherapy treatments in 3D using polymer gel dosimeters and optical computed tomography
. [Internet] [Thesis]. Queens University; 2008. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/1974/1638.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Holmes O. Validation of conformal radiotherapy treatments in 3D using polymer gel dosimeters and optical computed tomography
. [Thesis]. Queens University; 2008. Available from: http://hdl.handle.net/1974/1638
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Delft University of Technology
7.
van Aert, Emy (author).
Gel dosimetry for a MR-linac: magnetic field and time dependency.
Degree: 2020, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:4408f7c6-d16f-4cab-90c0-60dbf03d8a27
► The goal of this research was to perform a 3D end-to-end test on a MR-linac to check the whole workflow using a clinical treatment plan.…
(more)
▼ The goal of this research was to perform a 3D end-to-end test on a MR-linac to check the whole workflow using a clinical treatment plan. Dosimetric
gel was used to obtain 3D spatial information, with the phantom in the same position for irradiation and scanning. In order to achieve this, fundamental elements of
gel dosimetry needed to be investigated. In the MR-linac, irradiation is delivered in the presence of a permanent magnetic field. Therefore, the dosimetric response within a 1.5 T magnetic field should be validated. It is also important to investigate the time-dependence of the
gel. It is preferable to read-out the gels within approximately one hour, so that the phantom does not have to be moved. Ideally, scanning and irradiation would be done at the same time, to see the dynamical dose delivery. The VIPAR
gel was used for this research. The experiments demonstrated that R2 values for doses irradiated with magnetic field were the same as R2 values for the same dose irradiated without magnetic field. R2 values are still proportional to the dose. It was also shown that it is possible to scan the phantom within 20 minutes after irradiation. Sensitivity is at its highest after approximately 8 hours and stays stable afterwards, so scanning after 8 hours will improve the read-out accuracy. It was also possible to make a fit for the R2 versus time plots, which makes it possible to correct for change over time. The fit can be divided in two linear parts if time is plotted on a logarithmic scale, one fit for the time points before 7 hours, one for the time points after 7 hours. The partial doses acquired by the
gel during radiation delivery were estimated. The equivalent R2 values then agreed with the extrapolated fit to within 4%. This is a good indication that dynamic
gel (4D)
dosimetry may be achievable. A protocol for a relative end-to-end test was also developed. From the preliminary results, it appeared that a relative end-to-end test can be performed with the read-out of
gel within 1 hour. A new MR sequence needs to be developed. For this end-to-end test, the sequence needs to scan a larger volume with a higher resolution, therefore, the scan time will increase and real-time
dosimetry will not be possible. Changing the MR sequence might also change the optimal irradiation-scanning interval and the R2 versus time curve. To perform absolute
dosimetry, an extra calibration would be required.
Advisors/Committee Members: Denkova, Antonia (mentor), Wolthaus, Jochem (mentor), Woodings, Simon (mentor), Schaart, Dennis (graduation committee), Djanashvili, Kristina (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: gel dosimetry; MR-linac; magnetic field
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
van Aert, E. (. (2020). Gel dosimetry for a MR-linac: magnetic field and time dependency. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:4408f7c6-d16f-4cab-90c0-60dbf03d8a27
Chicago Manual of Style (16th Edition):
van Aert, Emy (author). “Gel dosimetry for a MR-linac: magnetic field and time dependency.” 2020. Masters Thesis, Delft University of Technology. Accessed April 11, 2021.
http://resolver.tudelft.nl/uuid:4408f7c6-d16f-4cab-90c0-60dbf03d8a27.
MLA Handbook (7th Edition):
van Aert, Emy (author). “Gel dosimetry for a MR-linac: magnetic field and time dependency.” 2020. Web. 11 Apr 2021.
Vancouver:
van Aert E(. Gel dosimetry for a MR-linac: magnetic field and time dependency. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Apr 11].
Available from: http://resolver.tudelft.nl/uuid:4408f7c6-d16f-4cab-90c0-60dbf03d8a27.
Council of Science Editors:
van Aert E(. Gel dosimetry for a MR-linac: magnetic field and time dependency. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:4408f7c6-d16f-4cab-90c0-60dbf03d8a27
University of Adelaide
8.
Ramm, Daniel Paul Norman.
An optical computed tomography scanner for three dimensional gel dosimetry of radiotherapy dose distributions.
Degree: 2018, University of Adelaide
URL: http://hdl.handle.net/2440/119799
► Clinical radiotherapy treatments using linear accelerator (linac) generated megavoltage xray beams are planned using computer models that calculate patient specific three dimensional (3D) radiation dose…
(more)
▼ Clinical radiotherapy treatments using linear accelerator (linac) generated megavoltage xray
beams are planned using computer models that calculate patient specific three
dimensional (3D) radiation dose distributions. Treatment planning system (TPS) calculated
doses are evaluated by clinicians to ensure suitable dose coverage of targeted tumours and
the avoidance of excessive doses to normal tissues. The accuracy of the TPS must be
validated by measurement to ensure correct patient treatments. Traditional radiotherapy
dosimeters do not measure dose entirely in 3D. They effectively ‘spot check’ accuracy at
discrete points or planes, without the ability to fully visualise measured dose distributions
in true 3D. True 3D
dosimetry systems have been a
subject of research for more than 3
decades.
Gel dosimetry with optical computed tomography (CT) scanning using visible
light wavelengths has been under investigation and development for much of this time. A
lack of clinical uptake of the systems developed to date suggests that there are deficiencies
or unappealing aspects, such as optical CT scanner maintenance and reliance upon optical
expertise. Dosimetric accuracy of these systems also requires improvement, closer to
accepted clinical dosimeters. In this work it was postulated that an optical CT scanner
could be developed that is more efficient, practical and accurate than those demonstrated
previously. This would address key aspects relating to clinical appeal. A specific
application of stereotactic radiosurgery was targeted, where small dose distributions are
delivered with high spatial accuracy to cranial tumours. Improvements in the practicality and efficiency of optical CT scanning were initially
sought by elimination of the need for a refractive index (RI) matching fluid bath for
scanning
gel dosimeter samples. Optical simulations were used to investigate and identify
suitable optical geometry that would enable fluid-less scanning for tomographic
reconstruction. A prototype fluid-less optical CT scanner was constructed and the proof of
concept was demonstrated using ferrous xylenol orange
gel (FXG). The next phase of work
was to develop the
dosimetry system further, striving for dosimetric accuracy. The
properties of the FXG dosimeter were studied by characterising the dose response, dose
development, ion diffusion and thermochromism. The scanner was refined by addressing
imaging artefacts, the addition of a reference detector and the development of a cuvette
based dose calibration procedure. Standard procedures for
gel manufacturing and handling,
and for optical CT operation were developed to improve reproducibility of results. The
system’s performance was assessed and its utility was demonstrated in the clinical
application of linac radiosurgery and was also extended to brachytherapy 192Ir source
verifications.
Further improvements of system practicality and measurement quality were proposed by
the concept of dual wavelength scanning. A second laser of a different wavelength…
Advisors/Committee Members: Penfold, Scott (advisor), School of Physical Sciences (school).
Subjects/Keywords: Radiotherapy; Gel dosimetry; Optical CT scanner; 3D dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Ramm, D. P. N. (2018). An optical computed tomography scanner for three dimensional gel dosimetry of radiotherapy dose distributions. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/119799
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Ramm, Daniel Paul Norman. “An optical computed tomography scanner for three dimensional gel dosimetry of radiotherapy dose distributions.” 2018. Thesis, University of Adelaide. Accessed April 11, 2021.
http://hdl.handle.net/2440/119799.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Ramm, Daniel Paul Norman. “An optical computed tomography scanner for three dimensional gel dosimetry of radiotherapy dose distributions.” 2018. Web. 11 Apr 2021.
Vancouver:
Ramm DPN. An optical computed tomography scanner for three dimensional gel dosimetry of radiotherapy dose distributions. [Internet] [Thesis]. University of Adelaide; 2018. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/2440/119799.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Ramm DPN. An optical computed tomography scanner for three dimensional gel dosimetry of radiotherapy dose distributions. [Thesis]. University of Adelaide; 2018. Available from: http://hdl.handle.net/2440/119799
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Cincinnati
9.
Sandwall, Peter A, II.
Spatial Dosimetry with Violet Diode Laser-Induced
Fluorescence of Water-Equivalent Radio-Fluorogenic Gels.
Degree: PhD, Engineering and Applied Science: Nuclear and
Radiological Engineering, 2014, University of Cincinnati
URL: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397477646
► The following work describes investigations of spatial dosimetry using laser-induced fluorescence of a radio-fluorogenic detector embedded within water-equivalent media. The chemical composition of a gelatin-based…
(more)
▼ The following work describes investigations of spatial
dosimetry using laser-induced fluorescence of a radio-fluorogenic
detector embedded within water-equivalent media. The chemical
composition of a gelatin-based coumarin-3-carboxylic acid detector
was investigated and dose response characterized. Violet diode
(405nm) excitation sources were explored and laser-induced
fluorescence (LIF) employed to obtain the pattern of fluorescent
emission yielding images of the integrated spatial dose
distribution. The design of a three-dimensional reader is proposed
to provide a foundation for future work. Radio-fluorogenic
processes create fluorescent products in response to ionizing
radiation. Water radiolysis produced by ionizing radiation yields
hydroxyl free radicals that readily hydroxylate
coumarin-3-carboxylic acid to 7-hydroxy-coumarin-3-carboxylic acid,
a derivative of umbelliferone. Umbelliferone is a known
fluorophore, exhibiting peak excitation in the UV to near UV range
of 365-405nm with a visible 445nm blue emission.
Coumarin-3-carboxlyic acid has been studied in an aqueous gelatin
matrix. The radio-fluorogenic coumarin-gelatin detector has been
shown to respond to an absorbed dose of ionizing radiation in a
measureable manner. The detector was studied with respect to
concentration of gelatin and coumarin in the presence of pH
buffers. Dose response of the detector was investigated with regard
to ionizing radiation type, energy, and rate of irradiation.
Results demonstrate a functional detector.Patterns of energy
deposition were formed in response to ionizing radiation produced
by a sealed-source of radioactive Ir-192 embedded in the gelatin
matrix of the detector. Spatial distributions of absorbed dose were
recorded and analyzed as a function of fluorescent emission. The
distribution of energy deposition was imaged with LIF excitation by
a divergent beam of 405nm light and determined by analysis of
digital image pixel intensity values displaying the 445nm
fluorescent emission. Results demonstrate spatial
dosimetry proof
of principle.A basic dedicated reader system was fabricated
employing LIF. Images of fluorescent emission excitation profiles
were obtained in multiple aqueous samples and processed to obtain a
dose response. Design of an optical reader system for the
radio-fluorogenic detector is explained and a three-dimensional
dosimetry system proposed. Three-dimensional imaging principles
with LIF have been illuminated.
Advisors/Committee Members: Spitz, Henry (Committee Chair).
Subjects/Keywords: Nuclear Engineering; Radio-fluorogenic; gel dosimetry; radiation dosimetry; spatial dosimetry; phantom; water-equivalent
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Sandwall, Peter A, I. (2014). Spatial Dosimetry with Violet Diode Laser-Induced
Fluorescence of Water-Equivalent Radio-Fluorogenic Gels. (Doctoral Dissertation). University of Cincinnati. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397477646
Chicago Manual of Style (16th Edition):
Sandwall, Peter A, II. “Spatial Dosimetry with Violet Diode Laser-Induced
Fluorescence of Water-Equivalent Radio-Fluorogenic Gels.” 2014. Doctoral Dissertation, University of Cincinnati. Accessed April 11, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397477646.
MLA Handbook (7th Edition):
Sandwall, Peter A, II. “Spatial Dosimetry with Violet Diode Laser-Induced
Fluorescence of Water-Equivalent Radio-Fluorogenic Gels.” 2014. Web. 11 Apr 2021.
Vancouver:
Sandwall, Peter A I. Spatial Dosimetry with Violet Diode Laser-Induced
Fluorescence of Water-Equivalent Radio-Fluorogenic Gels. [Internet] [Doctoral dissertation]. University of Cincinnati; 2014. [cited 2021 Apr 11].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397477646.
Council of Science Editors:
Sandwall, Peter A I. Spatial Dosimetry with Violet Diode Laser-Induced
Fluorescence of Water-Equivalent Radio-Fluorogenic Gels. [Doctoral Dissertation]. University of Cincinnati; 2014. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397477646
10.
Roberto Kenji Sakuraba.
Desenvolvimento de um sistema de verificação dosimétrica tridimensional utilizando Solução Fricke gel na aplicação para a verificação da Radioterapia em Arco Modulado Volumétrico (VMAT) nos tratamentos com movimentação do alvo pela respiração.
Degree: 2015, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03032016-091027/
► A Radioterapia em arco modulado volumétrico (VMAT) é uma das modalidades mais avançadas em teleterapia para o tratamento de câncer. Os diversos avanços tecnológicos, bem…
(more)
▼ A Radioterapia em arco modulado volumétrico (VMAT) é uma das modalidades mais avançadas em teleterapia para o tratamento de câncer. Os diversos avanços tecnológicos, bem como a evolução das técnicas de tratamento tornaram o VMAT como uma das modalidades de estado da arte para o tratamento de alguns cânceres. Parte deste avanço é creditada à melhoria na acurácia e na prescrição de dose absorvida recomendada ao paciente ao longo dos anos. Este avanço permite que atualmente seja possível realizar os cálculos dosimétricos, por meio de sistemas de planejamento computadorizado, considerando as heterogeneidades dos pacientes, tais como: tecidos e órgãos com composições diferentes da água (meio de referência em radioterapia), contorno do paciente individualizado e o movimento dos tumores com a respiração. Tais avanços demandam o controle de qualidade destas ferramentas, com objetivo de assegurar que todo o processo de tratamento seja satisfatório e
acurado. A comunidade dispõe poucos sistemas experimentais capazes de avaliar, considerando os níveis de incerteza, se os sistemas de planejamento computadorizados são aptos a considerar a movimentação dos alvos nos tratamentos com VMAT. Neste trabalho serão apresentados os resultados obtidos empregando um objeto simulador Fricke Xylenol Gel, com capacidade de mensurar as diferenças introduzidas pela movimentação, utilizando Imagem por Ressonância Magnética - MRI e comparando qualitativamente e quantitativamente os resultados. São discutidas as principais etapas de desenvolvimento deste objeto simulador, seus resultados experimentais, conclusões.
Volumetric Modulated Arc Therapy (VMAT) is one of the methods most commonly used in teletherapy to treat cancer. The various technological advances and the evolution of treatment techniques made the VMAT as one of the state of the art methods for the treatment of some cancers. Part of this improvement is credited to improvements in
accuracy and prescription dose absorbed recommended to the patient over the years. This advance allows currently is possible to perform dosimetric calculations by means of the computerized planning system, considering the heterogeneity of patients, such as tissues and organs with different water compositions medium (reference radiation), and individual patient contour the movement of tumors breathing. Such advances require quality control of these tools, in order to ensure that the entire treatment process is satisfactory and accurate. Up to now, the community lacks an experimental system capable of evaluating, considering the uncertainty levels if the computerized planning systems are able to consider the movement of targets in the treatments with VMAT. In this paper, will be presented the results obtained with the phantom Fricke Xylenol Gel, capable of measuring the differences introduced by movement using the Magnetic Resonance Image - MRI and compared qualitatively and
quantitatively. The main stages of the phantom development, their experimental results, conclusions and comparisons with other…
Advisors/Committee Members: Letícia Lucente Campos Rodrigues, Adelmo Jose Giordani, Felícia Del Gallo Rocha, Orlando Rodrigues Junior, Vitor Vivolo.
Subjects/Keywords: 4 dimensões; dosimetria; gel; radioterapia; dosimetry; gating; gel; radiotherapy
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Sakuraba, R. K. (2015). Desenvolvimento de um sistema de verificação dosimétrica tridimensional utilizando Solução Fricke gel na aplicação para a verificação da Radioterapia em Arco Modulado Volumétrico (VMAT) nos tratamentos com movimentação do alvo pela respiração. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03032016-091027/
Chicago Manual of Style (16th Edition):
Sakuraba, Roberto Kenji. “Desenvolvimento de um sistema de verificação dosimétrica tridimensional utilizando Solução Fricke gel na aplicação para a verificação da Radioterapia em Arco Modulado Volumétrico (VMAT) nos tratamentos com movimentação do alvo pela respiração.” 2015. Doctoral Dissertation, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03032016-091027/.
MLA Handbook (7th Edition):
Sakuraba, Roberto Kenji. “Desenvolvimento de um sistema de verificação dosimétrica tridimensional utilizando Solução Fricke gel na aplicação para a verificação da Radioterapia em Arco Modulado Volumétrico (VMAT) nos tratamentos com movimentação do alvo pela respiração.” 2015. Web. 11 Apr 2021.
Vancouver:
Sakuraba RK. Desenvolvimento de um sistema de verificação dosimétrica tridimensional utilizando Solução Fricke gel na aplicação para a verificação da Radioterapia em Arco Modulado Volumétrico (VMAT) nos tratamentos com movimentação do alvo pela respiração. [Internet] [Doctoral dissertation]. University of São Paulo; 2015. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03032016-091027/.
Council of Science Editors:
Sakuraba RK. Desenvolvimento de um sistema de verificação dosimétrica tridimensional utilizando Solução Fricke gel na aplicação para a verificação da Radioterapia em Arco Modulado Volumétrico (VMAT) nos tratamentos com movimentação do alvo pela respiração. [Doctoral Dissertation]. University of São Paulo; 2015. Available from: http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03032016-091027/
McMaster University
11.
Eyadeh, Molham.
The Development of a Transparent Poly(vinyl alcohol) Radiochromic Cryogel Dosimeter and Optical Detection Methods.
Degree: PhD, 2015, McMaster University
URL: http://hdl.handle.net/11375/18634
► In radiation therapy, gel dosimetry is used to measure radiation doses for treatment verification. Gel dosimeters have the ability to record dose information in three…
(more)
▼ In radiation therapy, gel dosimetry is used to measure radiation doses for treatment verification. Gel dosimeters have the ability to record dose information in three dimensions. The objective of this thesis was to fabricate a transparent cryogel radiochromic dosimeter with poly(vinyl alcohol) (PVA) as the gelling agent. A transparent dosimeter may be analyzed using an optical read out technique, which is desirable. PVA cryogels can be made transparent by adding dimethyl sulfoxide (DMSO).
Measurements of dose response were performed and various parameters were adjusted, including: numbers of freeze-thaw cycles (FTCs); concentrations of PVA; DMSO concentration. The measured absorption coefficient increased linearly with dose up to approximately 10 Gy. The sensitivity was increased for higher PVA concentrations, larger numbers of FTCs, and less DMSO. The resulting dosimeter was stable and showed no significant dose rate or photon energy dependence.
The cryogels were later formed into 5 mm thick films and used as a tool for performing in vivo dosimetry. The dose response of the radiochromic bolus was characterized by irradiating it on a flat surface at different gantry angles. The dose measured in the bolus was approximately 0.80 of the dose measured by Gafchromic film at the skin surface, taking the obliquity into account. IMRT treatments were delivered to a RANDO phantom. The radiochromic bolus was used to measure skin surface dose in two dimensions at various locations. The 0.80 factor was used to calibrate the bolus, which was then compared to an accompanying film measurement. Good agreement was observed between the measurements (>95% gamma pass rate), suggesting the radiochromic bolus may be suitable for in vivo applications.
The radiochromic bolus was then used to evaluate errors associated with the breath hold technique often used with left chest wall tangential irradiation. Treatment plan incorporating the radiochromic bolus was delivered at the planned position and shifted anterior-posteriorly (A/P) up to 5 mm. Large discrepancies from the planned two dimensional skin surface distribution were observed for shifts as small as 3 mm in the A/P direction. The study demonstrated that the cryogel was sensitive to small positioning uncertainties for chest wall irradiations, potentially allowing for the detection of clinically relevant errors.
Other potential formulations of PVA-based radiochromic cryogels are discussed briefly as avenues to future research projects.
Thesis
Doctor of Philosophy (PhD)
Advisors/Committee Members: Diamond, Kevin, Medical Physics.
Subjects/Keywords: Gel Dosimetry; Radiation Dosimetry; Radiochromic Dosimeter; Radiotherapy; Poly(vinyl Alcohol)PVA; Cryogel
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Eyadeh, M. (2015). The Development of a Transparent Poly(vinyl alcohol) Radiochromic Cryogel Dosimeter and Optical Detection Methods. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/18634
Chicago Manual of Style (16th Edition):
Eyadeh, Molham. “The Development of a Transparent Poly(vinyl alcohol) Radiochromic Cryogel Dosimeter and Optical Detection Methods.” 2015. Doctoral Dissertation, McMaster University. Accessed April 11, 2021.
http://hdl.handle.net/11375/18634.
MLA Handbook (7th Edition):
Eyadeh, Molham. “The Development of a Transparent Poly(vinyl alcohol) Radiochromic Cryogel Dosimeter and Optical Detection Methods.” 2015. Web. 11 Apr 2021.
Vancouver:
Eyadeh M. The Development of a Transparent Poly(vinyl alcohol) Radiochromic Cryogel Dosimeter and Optical Detection Methods. [Internet] [Doctoral dissertation]. McMaster University; 2015. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/11375/18634.
Council of Science Editors:
Eyadeh M. The Development of a Transparent Poly(vinyl alcohol) Radiochromic Cryogel Dosimeter and Optical Detection Methods. [Doctoral Dissertation]. McMaster University; 2015. Available from: http://hdl.handle.net/11375/18634
McMaster University
12.
Al Rashed, Hailah.
THE DEVELOPMENT OF A LOW DENSITY RADIOCHROMIC GEL DOSIMETER.
Degree: MSc, 2019, McMaster University
URL: http://hdl.handle.net/11375/24092
► This research aims to develop a tissue-mimicking material and produce a 3D gelatin that has density of approximately a human lung, which is in the…
(more)
▼ This research aims to develop a tissue-mimicking material and produce a 3D gelatin that has density of approximately a human lung, which is in the ranges of (0.25 – 0.35) g/cm3. Tissue equivalent models are important in order to study the radiation dose planned for patients. To achieve the desired density of a human tissue, different types of gelatin were whisked for 300 seconds using a typical hand mixer. The mechanical properties of the gelatin mixtures, standard and foamed, were evaluated by applying different forces.
The mechanical properties for the gels were measured using an indentation technique, which showed that the gels act as elastic materials. The mechanical properties of the foams were also evaluated. Mixtures that contained 300 bloom gelatin, glycerol, and sorbitol, were whisked for 60, 180, 300 seconds to achieve different densities evaluated by CT imaging. The density of the180 - and 300 - seconds gelatin foams were found to be 0.33 ± 0.16 and 0.33 0.052 g/cm3, respectively, which is similar to the human lung density. Finally, FXO gel sheets and the FXO foam sheets were irradiated and the radiosensitivity quantified by measuring transmission using a spectrometer. The change in the attenuation coefficient was linear with dose.
Thesis
Master of Science (MSc)
Advisors/Committee Members: Diamond, Kevin, Radiation Sciences (Medical Physics/Radiation Biology).
Subjects/Keywords: Gel Dosimetry; Radiation Dosimetry; Radiochromic Dosimeter; Radiotherapy; Quality Assurance (QA); Gelatin; Two dimensional; Three dimensional
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Al Rashed, H. (2019). THE DEVELOPMENT OF A LOW DENSITY RADIOCHROMIC GEL DOSIMETER. (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/24092
Chicago Manual of Style (16th Edition):
Al Rashed, Hailah. “THE DEVELOPMENT OF A LOW DENSITY RADIOCHROMIC GEL DOSIMETER.” 2019. Masters Thesis, McMaster University. Accessed April 11, 2021.
http://hdl.handle.net/11375/24092.
MLA Handbook (7th Edition):
Al Rashed, Hailah. “THE DEVELOPMENT OF A LOW DENSITY RADIOCHROMIC GEL DOSIMETER.” 2019. Web. 11 Apr 2021.
Vancouver:
Al Rashed H. THE DEVELOPMENT OF A LOW DENSITY RADIOCHROMIC GEL DOSIMETER. [Internet] [Masters thesis]. McMaster University; 2019. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/11375/24092.
Council of Science Editors:
Al Rashed H. THE DEVELOPMENT OF A LOW DENSITY RADIOCHROMIC GEL DOSIMETER. [Masters Thesis]. McMaster University; 2019. Available from: http://hdl.handle.net/11375/24092
13.
Alves, Anderson Vinicius Silva.
Desenvolvimento e caracterização de géis Fricke em matriz de PVA-GTA para dosimetria 3D em radioterapia.
Degree: 2019, Pós-Graduação em Física; UFS
URL: http://ri.ufs.br/jspui/handle/riufs/11334
► Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Three-dimensional dosimetry is one of the most advanced techniques for dosimetry in radiotherapy. The…
(more)
▼ Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Three-dimensional dosimetry is one of the most advanced techniques for dosimetry in radiotherapy. The conformed dose administered to radiotherapy results in complex spatial dose distributions, with large dose gradients in small volumes, which makes quality assurance difficult with the traditional methods. Gel dosimetry is a developmental technique based on tissueequivalent gel matrices, which behaves as a continuous three-dimensional dosimeter, preserving spatial information, which can be revealed with imaging techniques. In this research, the methods of producing the Fricke gel with a hydrogel matrix of polyvinyl alcohol cross-linked with glutaraldehyde, its variation of the optical absorption, that allow the dose-response curve to be obtained, its sensitivity, the pre- and post-irradiation stability, and the possibility of ligand and metal ion substitution. The
results show that the generated dosimeter has a good sensitivity, with a good linearity range, of approximately 35 Gy, and also good pre- and post-irradiation stability, even under adverse storage conditions. A replacement of ligand and metal ion are promissing. The ligand methylthymol blue showed great potential against the well established xylenol orange.
A dosimetria tridimensional é a técnica recente mais promissora para dosimetria em radioterapia. A dose conformal administrada na radioterapia moderna resulta em distribuições espaciais complexas de doses, com grandes gradientes de dose em pequenos volumes, o que dificulta o controle de qualidade com métodos tradicionais. A dosimetria em gel é uma técnica em fase de desenvolvimento baseada em matrizes tecido-equivalentes na forma de gel, que se comportam como dosímetros tridimensionais contínuos, preservando a informação espacial, que pode ser revelada posteriormente com técnicas de imagiologia. Nesta pesquisa, foram
investigados métodos de produção do gel Fricke com a matriz hidrogélica de álcool polivinílico reticulado com glutaraldeído, sua variação de absorção óptica, que possibilita a obtenção da sua curva dose-resposta, sua sensibilidade, estabilidade pré- e pós irradiação e a possibilidade da substituição de ligante e íon sensível. Os resultados mostram que o dosímetro produzido possui boa sensibilidade, com boa faixa de linearidade, de até aproximadamente 35 Gy, e também boa estabilidade pré- e pós-irradiação, mesmo em condições adversas de armazenamento. A substituição do ligante e do íon sensível se mostraram promissores. O ligante azul de metiltimol demonstrou grande potencial frente ao bem estabelecido alaranjado de xilenol.
São Cristóvão, SE
Advisors/Committee Members: Souza, Susana de Oliveira.
Subjects/Keywords: Radioterapia; Gel Fricke; Dosimetria; Radiotherapy; Fricke gel; Dosimetry; CIENCIAS EXATAS E DA TERRA::FISICA
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Alves, A. V. S. (2019). Desenvolvimento e caracterização de géis Fricke em matriz de PVA-GTA para dosimetria 3D em radioterapia. (Doctoral Dissertation). Pós-Graduação em Física; UFS. Retrieved from http://ri.ufs.br/jspui/handle/riufs/11334
Chicago Manual of Style (16th Edition):
Alves, Anderson Vinicius Silva. “Desenvolvimento e caracterização de géis Fricke em matriz de PVA-GTA para dosimetria 3D em radioterapia.” 2019. Doctoral Dissertation, Pós-Graduação em Física; UFS. Accessed April 11, 2021.
http://ri.ufs.br/jspui/handle/riufs/11334.
MLA Handbook (7th Edition):
Alves, Anderson Vinicius Silva. “Desenvolvimento e caracterização de géis Fricke em matriz de PVA-GTA para dosimetria 3D em radioterapia.” 2019. Web. 11 Apr 2021.
Vancouver:
Alves AVS. Desenvolvimento e caracterização de géis Fricke em matriz de PVA-GTA para dosimetria 3D em radioterapia. [Internet] [Doctoral dissertation]. Pós-Graduação em Física; UFS; 2019. [cited 2021 Apr 11].
Available from: http://ri.ufs.br/jspui/handle/riufs/11334.
Council of Science Editors:
Alves AVS. Desenvolvimento e caracterização de géis Fricke em matriz de PVA-GTA para dosimetria 3D em radioterapia. [Doctoral Dissertation]. Pós-Graduação em Física; UFS; 2019. Available from: http://ri.ufs.br/jspui/handle/riufs/11334
14.
Juliana Fernandes Pavoni.
Dosimetria tridimensional por imagens de ressonância magnética com gel MAGIC modificado.
Degree: 2009, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-27042010-171038/
► Os avanços nas técnicas de tratamento com radiação ionizante estão gerando distribuições de dose muito complexas que precisam ser verificadas antes da aplicação do tratamento…
(more)
▼ Os avanços nas técnicas de tratamento com radiação ionizante estão gerando distribuições de dose muito complexas que precisam ser verificadas antes da aplicação do tratamento no paciente. Diversos dosímetros já foram propostos para esta verificação, mas o que vem apresentando os melhores resultados são os géis poliméricos que permitem a visualização tridimensional da dose. Neste trabalho desenvolvemos um gel dosimétrico do tipo MAGIC com componentes nacionais, para baratear o custo e assim, facilitar a sua aplicação na rotina clínica. Nós adicionamos formaldeído ao gel para aumentar seu ponto de fusão e facilitar seu manuseio em temperatura ambiente. A avaliação das doses foi feita através da relaxometria em imagens de ressonância magnética nuclear (IRMN). Foi encontrada uma resposta linear para dose de até 15Gy e uma dependência energética significativa para feixes de baixa energia (kVp), enquanto que para alta energia (MV) a dependência
encontrada foi pequena. A variação da resposta do dosímetro em função da taxa de dose da irradiação foi menor que 5% nas taxas de 100 a 600cGy/min. A adição de formaldeído não eliminou a dependência da resposta do dosímetro para variações na temperatura durante a aquisição das IRMN, já a integridade da distribuição de dose se manteve inalterada por um período de três meses na irradiação de um campo blindado ao meio. Medidas tridimensionais de distribuição de dose foram realizadas para dois planos de radioterapia com intensidade modulada de feixe o primeiro em um acelerador linear e o segundo em um equipamento de tomoterapia, grande semelhança entre a sobreposição das isodoses e dos perfis de dose das imagens medidas com o gel e esperadas pelo sistema de planejamento (TPS) foi encontrada. A avaliação realmente tridimensional foi feita com os histogramas dose-volume (DVH), sendo que uma sobreposição entre os DVHs calculados para o volume planejado e os esperados pelo TPS foi encontrada
nos dois planejamentos. Por tudo o que foi estudado, pode-se concluir que a modificação realizada no gel MAGIC resultou em um dosímetro de fácil manuseio que pode ser aplicado para medidas tridimensionais.
Advances in the treatment techniques with ionizing radiation are resulting in complex dose distributions that need to be verified before the application of the treatment in the patient. Several dosimeters have been suggested for this application, but polymeric gel dosimeters are presenting the best results so far, since they allow three dimensional dose visualization, are tissue equivalent, don\'t have dependence with angular distribution of the incident radiation and have a high spatial resolution. In this work a polymeric gel dosimeter with national components, to reduce de costs and facilitate its introduction in the clinical practice was developed. Formaldehyde was added to the gel formulation to increase its melting temperature and facilitate its use in typical room
temperatures found in our country. Dose response analysis was done using nuclear magnetic resonance…
Advisors/Committee Members: Oswaldo Baffa Filho, Thomaz Ghilardi Netto, Harley Francisco de Oliveira, Elisabeth Mateus Yoshimura.
Subjects/Keywords: dosimetria; gel; MAGIC; dosimetry; gel; MAGIC
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Pavoni, J. F. (2009). Dosimetria tridimensional por imagens de ressonância magnética com gel MAGIC modificado. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-27042010-171038/
Chicago Manual of Style (16th Edition):
Pavoni, Juliana Fernandes. “Dosimetria tridimensional por imagens de ressonância magnética com gel MAGIC modificado.” 2009. Doctoral Dissertation, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-27042010-171038/.
MLA Handbook (7th Edition):
Pavoni, Juliana Fernandes. “Dosimetria tridimensional por imagens de ressonância magnética com gel MAGIC modificado.” 2009. Web. 11 Apr 2021.
Vancouver:
Pavoni JF. Dosimetria tridimensional por imagens de ressonância magnética com gel MAGIC modificado. [Internet] [Doctoral dissertation]. University of São Paulo; 2009. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-27042010-171038/.
Council of Science Editors:
Pavoni JF. Dosimetria tridimensional por imagens de ressonância magnética com gel MAGIC modificado. [Doctoral Dissertation]. University of São Paulo; 2009. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-27042010-171038/
15.
Shiva do Valle Camargo.
Confecção e caracterização de dosímetros luminescentes de cerâmicas de BaTiO3 nanoestruturadas.
Degree: 2013, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/3/3140/tde-11072014-093623/
► Conforme pesquisas realizadas na literatura, o estudo do Titanato de Bário (BTO) na dosimetria é inédito, este material foi escolhido porque exibe propriedades luminescentes, demonstradas…
(more)
▼ Conforme pesquisas realizadas na literatura, o estudo do Titanato de Bário (BTO) na dosimetria é inédito, este material foi escolhido porque exibe propriedades luminescentes, demonstradas em experimentos de medidas de espectros de emissão. Para a confecção do BTO fez-se o uso da técnica química Sol-Gel, foi produzido amostras de BTO Puro, BTO dopado e co-dopado com diversas terras-raras. Todas as amostras produzidas sofreram calcinações com temperaturas definidas em 800, 1000 e 1200°C. As dopagens foram realizadas com os seguintes elementos terras-raras: Nd, Tb, Eu, Yb, Er, Pr, e as amostras co-dopadas foram com Tb/Eu e Yb/Er; no total foram confeccionadas trinta e uma amostras. No estudo de redução de massa foi constatada uma redução de metade das massas das amostras durante o processo de calcinação. Nas análises de Termoluminescência (TL) pelo menos uns dos tipos de calcinações apresentaram picos TL, com exceção das amostras co-dopadas com Tb/Eu.
As amostras dopadas com Eu e Tb se destacaram nas análises das respostas termoluminescentes. A amostra com Tb e calcinada a 1200°C forneceu pico TL entre 90 a 200°C, e a dopada com Eu (1mol%) e calcinado a 1000°C apresentou picos TL em 110°C e 370°C. A mínima dose detectável para o pico de 110°C foi de 119 mGy e para o pico de 370°C foi de 143 mGy. As análises de MEV mostraram que as micrografias das amostras de BTO dopado tanto com Tb, quanto com Eu apresentaram superfícies porosas, diferentemente das Puras, que apresentaram superfície mais lisa. As análises de DRX indicaram uma fase tetragonal para as amostras Pura e dopadas com Eu (1 mol%), ambas calcinadas a 1000°C.
According to the literature, the study of Barium Titanate (BTO) for dosimetry is unpublished yet, this material was chosen because it exhibits luminescent properties, demonstrated in emission spectra experiments. To make the BTO samples the chemical sol-gel technique was used. Samples of BTO Pure, doped and
co-doped with different rare earths were made. All produced samples were calcinated with temperatures at 800, 1000 and 1200°C. The doping was performed with the following rare earths: Nd, Tb, Eu, Yb, Er, Pr, and some samples were co-doped with Tb / Eu and Yb / Er; in total were made thirty-one samples. In the study of weight reduction, a reduction, by half of the mass of raw material, was observed during the calcination process. In the TL analysis, at least one of the types (temperature) of calcinations provides TL peaks formation, except for the samples co-doped with Tb / Eu. The BTO: Eu and Tb provided the best TL response. The BTO: Tb and calcined at 1200°C showed TL peak at 90 to 200°C and the one doped with Eu (1mol%) and calcined at 1000°C supplied peaks at 110°C and 370°C. The minimum detectable dose to the TL peak at 110°C was 119 mGy and for TL peak at 370°C was 143 mGy. SEM analyzes showed that the micrographs of BTO samples doped with both Tb and Eu supplied porous
surfaces, unlike the pure sample, that showed smoother surface. XRD analyzes indicated a tetragonal phase to pure…
Advisors/Committee Members: Sonia Hatsue Tatumi, Juan Carlos Ramírez Mittani, Sebastião Gomes dos Santos Filho.
Subjects/Keywords: Dosimetria; Sol-Gel; Termoluminescência; Titanato de Bário; Barium Titanate; Dosimetry; Sol-Gel; Thermoluminescence
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Camargo, S. d. V. (2013). Confecção e caracterização de dosímetros luminescentes de cerâmicas de BaTiO3 nanoestruturadas. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/3/3140/tde-11072014-093623/
Chicago Manual of Style (16th Edition):
Camargo, Shiva do Valle. “Confecção e caracterização de dosímetros luminescentes de cerâmicas de BaTiO3 nanoestruturadas.” 2013. Masters Thesis, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/3/3140/tde-11072014-093623/.
MLA Handbook (7th Edition):
Camargo, Shiva do Valle. “Confecção e caracterização de dosímetros luminescentes de cerâmicas de BaTiO3 nanoestruturadas.” 2013. Web. 11 Apr 2021.
Vancouver:
Camargo SdV. Confecção e caracterização de dosímetros luminescentes de cerâmicas de BaTiO3 nanoestruturadas. [Internet] [Masters thesis]. University of São Paulo; 2013. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/3/3140/tde-11072014-093623/.
Council of Science Editors:
Camargo SdV. Confecção e caracterização de dosímetros luminescentes de cerâmicas de BaTiO3 nanoestruturadas. [Masters Thesis]. University of São Paulo; 2013. Available from: http://www.teses.usp.br/teses/disponiveis/3/3140/tde-11072014-093623/
Queensland University of Technology
16.
Asena, Andre.
Dosimetry in the vicinity of high-density materials in radiotherapy.
Degree: 2017, Queensland University of Technology
URL: https://eprints.qut.edu.au/103983/
► The success of radiation therapy treatments is largely dependent on the ability to accurately deliver the prescribed dose to a patient within a narrow tolerance.…
(more)
▼ The success of radiation therapy treatments is largely dependent on the ability to accurately deliver the prescribed dose to a patient within a narrow tolerance. However, the human body consists of many components, which vary in density and can cause treatment complications. In this research, a methodology is established whereby the effects of high-density medical implants on radiotherapy treatments can be quantified accurately and efficiently. A better understanding of the impact of these medical implants on radiotherapy dose distributions means more accurate treatments can be delivered with increased confidence, resulting in improved patient outcomes.
Subjects/Keywords: Radiotherapy; Gel dosimetry; high-density; implants; optical CT
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Asena, A. (2017). Dosimetry in the vicinity of high-density materials in radiotherapy. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/103983/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Asena, Andre. “Dosimetry in the vicinity of high-density materials in radiotherapy.” 2017. Thesis, Queensland University of Technology. Accessed April 11, 2021.
https://eprints.qut.edu.au/103983/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Asena, Andre. “Dosimetry in the vicinity of high-density materials in radiotherapy.” 2017. Web. 11 Apr 2021.
Vancouver:
Asena A. Dosimetry in the vicinity of high-density materials in radiotherapy. [Internet] [Thesis]. Queensland University of Technology; 2017. [cited 2021 Apr 11].
Available from: https://eprints.qut.edu.au/103983/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Asena A. Dosimetry in the vicinity of high-density materials in radiotherapy. [Thesis]. Queensland University of Technology; 2017. Available from: https://eprints.qut.edu.au/103983/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Victoria
17.
Johnston, Holly A.
An x-ray computed tomography polymer gel dosimetry system for complex radiation therapy treatment verification.
Degree: Dept. of Physics and Astronomy, 2013, University of Victoria
URL: http://hdl.handle.net/1828/4939
► X-ray computed tomography (CT) polymer gel dosimetry (PGD) is an attractive tool for three-dimensional (3D) radiation therapy (RT) treatment verification due to the availability of…
(more)
▼ X-ray computed tomography (CT) polymer
gel dosimetry (PGD) is an attractive tool for three-dimensional (3D) radiation therapy (RT) treatment verification due to the availability of CT scanners in RT clinics. Nevertheless, wide-spread use of the technique has been hindered by low signal-to-noise CT images largely resulting from
gel formulations with low radiation sensitivity. However, a new
gel recipe with enhanced dose sensitivity was recently introduced that shows great promise for use with CT readout. This dissertation describes development of an CT PGD system for 3D verification of RT treatments using the new
gel formulation. The work is divided into three studies:
gel characterization, commissioning of a multislice CT scanner and investigation of a dose rate dependence observed during
gel characterization.
The first component of this work examines the dosimetric properties of the new
gel formulation. The response of the
gel is found to be stable between 15 - 36 hours post-irradiation and excellent batch reproducibility is seen for doses between 0 - 28 Gy. A dose rate dependence is found for gels irradiated between 100 - 600 MU/min, indicating machine dose rate must be consistent for calibration and test irradiations to avoid dosimetric error. An example clinical application is also presented using an IMRT treatment verification that demonstrates the potential of the system for use in modern RT.
The second component of this work focuses on commissioning a multislice CT scanner for CT PGD. A new slice-by-slice background subtraction technique is introduced to account for the anode heel effect. Additional investigations show recommendations for optimizing image quality in CT PGD using a single slice machine also apply to multislice scanners. In addition, the consistency of CT numbers across the multislice detector array is found to be excellent for all slice thicknesses. Further work is performed to assess the tube load characteristics of the scanner and develop a scanning protocol for imaging large
gel volumes. Finally, images acquired throughout the volume of an unirradiated active
gel show variations in CT data across each image on the order of 7 HU. However, these variations are not expected to greatly influence
gel measurements as they are consistent throughout the
gel volume.
The third component of this work examines the dose rate dependence found during
gel characterization. Studies using
gel vials and 1 L cylinders indicate the response of the
gel does not depend on changes in mean dose rate on the order of seconds to minutes. However, the machine dose rate remains, indicating variations in dose rate on the order of milliseconds influence the response of the
gel. An attempt is made to mitigate the effect by increasing the concentration of antioxidant in the
gel system but results in reduced overall response. Further work is performed to determine if self-crosslinking of one of the
gel components contributes to the observed machine dose rate dependence.
In summary, this…
Advisors/Committee Members: Hilts, Michelle Louise (supervisor), Jirasek, Andrew (supervisor).
Subjects/Keywords: Medical Physics; Polymer Gel Dosimetry; X-ray Computed Tomography
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Johnston, H. A. (2013). An x-ray computed tomography polymer gel dosimetry system for complex radiation therapy treatment verification. (Thesis). University of Victoria. Retrieved from http://hdl.handle.net/1828/4939
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Johnston, Holly A. “An x-ray computed tomography polymer gel dosimetry system for complex radiation therapy treatment verification.” 2013. Thesis, University of Victoria. Accessed April 11, 2021.
http://hdl.handle.net/1828/4939.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Johnston, Holly A. “An x-ray computed tomography polymer gel dosimetry system for complex radiation therapy treatment verification.” 2013. Web. 11 Apr 2021.
Vancouver:
Johnston HA. An x-ray computed tomography polymer gel dosimetry system for complex radiation therapy treatment verification. [Internet] [Thesis]. University of Victoria; 2013. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/1828/4939.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Johnston HA. An x-ray computed tomography polymer gel dosimetry system for complex radiation therapy treatment verification. [Thesis]. University of Victoria; 2013. Available from: http://hdl.handle.net/1828/4939
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Minnesota
18.
Warmington, Leighton.
Three-dimensional dosimetry around small distributed high-Z materials.
Degree: PhD, Biophysical Sciences and Medical Physics, 2016, University of Minnesota
URL: http://hdl.handle.net/11299/188826
► Patients are increasingly undergoing radiotherapy procedures, in which small metals are implanted in the body for target localization for IGRT or targeted therapies. Previous, interface…
(more)
▼ Patients are increasingly undergoing radiotherapy procedures, in which small metals are implanted in the body for target localization for IGRT or targeted therapies. Previous, interface dosimetry studies focused high-Z materials irradiated by low energy beams where the dose enhancement is large. In the majority of the cases, they used one or two dimensional detectors. Therapeutic beams, however, are mostly 6 MV and higher with significantly less dose enhancement. Over the last decade, significant improvements in polymer gel dosimetry have been made allowing for improved 3D dose measurements. The purpose of this study was to better understand the dose around distributed high-Z materials irradiated by high energy photon beams and investigate the feasibility of 3D dose measurements. A Monte Carlo code was used to determine the effect of various foil configurations. The dosimetric effect of foil thickness, separation, energy and other factors were investigated. Software tools were also developed to process the data. These results were used to help identify suitable experimental setups. The dose around two foils was compared to the dose resulting from adding the dose of two single foils. The dose around a single foil was also compared to the dose around a fiduciary marker. Later on, we looked at how distributing the thickness of the high-Z foil over a wider area affected dose and how that compared to a to the dose around a single foil. Finally, we looked at the effect of pair production and how it affected the distribution of dose in select configurations. Several polymer gel dosimeter (PGD) were evaluated and two were selected for further study. Various formulations were investigated and procedures developed to meet the needs of the project. Materials compatibility studies were performed to ensure that there were no reactions between the PGD and inserted materials within the time frame of the studies. PGDs were manufactured and thin lead foils with the configuration determined earlier were inserted into the polymer gel. The PGDs was irradiated with 18 MV photons and the dose was quantified using MRI with a multiple spin echo technique for the measurement of the spin-spin relaxation rate (R2). The measured dose data were compared to theoretical data obtained from Monte Carlo experiments. The dose profiles around the foils from the PGD were in agreement with dose values from simulation. This project demonstrated that it is feasible to use polymer gel dosimetry to measure the fine dosimetric structures around a small metallic object. We also determined that material, foil thickness, separation and photon energy had the largest effect on the dose in-between a two foil configuration. When the foils were close, we found that the dose around the two foils was larger but not significantly different from the combined dose of two single foils with the same separation. We also found that the dose upstream and downstream of a distributed foil is less that the upstream and downstream dose around a single foil of equivalent…
Subjects/Keywords: 3D; Dose Enhancement; Dosimetry; Monte Carlo; Nanoparticle; Polymer Gel
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Warmington, L. (2016). Three-dimensional dosimetry around small distributed high-Z materials. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/188826
Chicago Manual of Style (16th Edition):
Warmington, Leighton. “Three-dimensional dosimetry around small distributed high-Z materials.” 2016. Doctoral Dissertation, University of Minnesota. Accessed April 11, 2021.
http://hdl.handle.net/11299/188826.
MLA Handbook (7th Edition):
Warmington, Leighton. “Three-dimensional dosimetry around small distributed high-Z materials.” 2016. Web. 11 Apr 2021.
Vancouver:
Warmington L. Three-dimensional dosimetry around small distributed high-Z materials. [Internet] [Doctoral dissertation]. University of Minnesota; 2016. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/11299/188826.
Council of Science Editors:
Warmington L. Three-dimensional dosimetry around small distributed high-Z materials. [Doctoral Dissertation]. University of Minnesota; 2016. Available from: http://hdl.handle.net/11299/188826
Louisiana State University
19.
Bruce, Paul Anthony.
The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT.
Degree: MS, Physical Sciences and Mathematics, 2003, Louisiana State University
URL: etd-0305103-143757
;
https://digitalcommons.lsu.edu/gradschool_theses/2336
► The sophistication of radiation therapy delivery techniques at Mary Bird Perkins Cancer Center (MBPCC) creates the need for an advanced dosimetric system that can quantify…
(more)
▼ The sophistication of radiation therapy delivery techniques at Mary Bird Perkins Cancer Center (MBPCC) creates the need for an advanced dosimetric system that can quantify and verify the dose distributions in three-dimensions. Current dosimetric systems perform this dose analysis in only one or two dimensions. This paper evaluates the application of BANG-3™ polymer gel dosimetry to quantify the 3-D dose distribution of Intensity-Modulated Radiation Therapy (IMRT) using a "step and shoot" approach. The gel was irradiated by 10 MV photons at a dose rate of 400 MU/min. Relaxation rate maps were computed from proton density and T2-weighted magnetic resonance images acquired with a GE Horizon 1.5T scanner; scans were performed 5 days and 2 months post-irradiation. The dose distribution within the gel was compared to the dose distribution calculated by the Pinnacle3 planning system. Three techniques were used for analysis: image subtraction, dose-volume analysis and contour analysis. Also, a dose correction factor was used to attempt to correct for excess dose delivered to the gel as the gels were erroneously placed in the treatment room two days prior to irradiation. Corrected 5-day post-irradiation dose maps show reasonable agreement with the Pinnacle3 plan. The absolute measurement error was +/-50 cGy; however, the relative errors were large compared to the total dose of 2 Gy delivered to the gel. Delivering a larger total dose should reduce the relative error to a reasonable magnitude. Exposure to light and other environmental factors caused substantial additional polymerization with time. The results of this project indicate that polymer gel dosimetry could be a useful routine 3D dosimetric technique at MBPCC. However, utilizing a commercial scanning service may simplify use of the gels.
Subjects/Keywords: gel dosimetry; polymer gel; gel calibration; dose deviation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bruce, P. A. (2003). The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT. (Masters Thesis). Louisiana State University. Retrieved from etd-0305103-143757 ; https://digitalcommons.lsu.edu/gradschool_theses/2336
Chicago Manual of Style (16th Edition):
Bruce, Paul Anthony. “The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT.” 2003. Masters Thesis, Louisiana State University. Accessed April 11, 2021.
etd-0305103-143757 ; https://digitalcommons.lsu.edu/gradschool_theses/2336.
MLA Handbook (7th Edition):
Bruce, Paul Anthony. “The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT.” 2003. Web. 11 Apr 2021.
Vancouver:
Bruce PA. The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT. [Internet] [Masters thesis]. Louisiana State University; 2003. [cited 2021 Apr 11].
Available from: etd-0305103-143757 ; https://digitalcommons.lsu.edu/gradschool_theses/2336.
Council of Science Editors:
Bruce PA. The use of the BANG-3 polymer gel to quantify the three-dimensional dose distribution of IMRT. [Masters Thesis]. Louisiana State University; 2003. Available from: etd-0305103-143757 ; https://digitalcommons.lsu.edu/gradschool_theses/2336
20.
Jéssica Caroline Lizar.
Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório.
Degree: 2017, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-30082017-152201/
► A radioterapia externa pós-operatória em mulheres diagnosticadas com câncer de mama em estágio inicial é tido como um procedimento padrão, no entanto durante o planejamento…
(more)
▼ A radioterapia externa pós-operatória em mulheres diagnosticadas com câncer de mama em estágio inicial é tido como um procedimento padrão, no entanto durante o planejamento para irradiação do volume alvo as possíveis incertezas dosimétricas introduzidas dado o movimento respiratório intrínseco da paciente são desconsideradas. Este estudo avalia não apenas a influência da respiração na distribuição tridimensional da dose, mas como essa distribuição se modifica dado a técnica radioterápica empregada para o tratamento. Três técnicas de planejamento foram analisadas: a radioterapia conformacional tridimensional (3D-RT) com filtros, a radioterapia com intensidade modulada (IMRT) usando planejamento direto e o IMRT inverso. A fim de simular o movimento de contração e expansão da caixa torácica, utilizou-se uma plataforma com amplitudes de oscilação pré-determinadas, sendo a frequência de oscilação provida por uma fonte de tensão variável. Para simular a
mama usou-se objetos simuladores semiesféricos preenchidos com
gel dosimétrico (MAGIC-f). Os planejamentos para cada técnica foram realizados sobre a mesma tomografia computadorizada (CT) do objeto simulador preenchido com água no modo estático. Foram produzidos três lotes de dosímetro
gel para o projeto, cada lote foi irradiado com uma técnica radioterápica diferente, sendo que cada lote inclui cinco objetos simuladores e um conjunto de nove tubos de calibração preenchidos com
gel MAGIC-f. O primeiro dos objetos simuladores é utilizado como referência, o segundo é irradiado no modo estático, os demais são irradiados em diferentes amplitudes, respectivamente: 0,34 cm, 0,88 cm e 1,22 cm. A informação volumétrica de dose foi obtida utilizando imagens por ressonância magnética nuclear (IRMN), para cada lote foram adquiridos IRMN com sequência multi spin echo e os mapas de relaxometria, que são associados à dose, foram extraídos em um software desenvolvido e aprimorado pelo nosso grupo
de pesquisa. A comparação quantitativa dos mapas de relaxometria dos objetos simuladores em movimento em relação ao modo estático foi realizado pelo índice gamma tridimensional (3% / 3mm / 15% Threshold). Para o 3D-RT a porcentagem de pontos aprovados do objeto estático em relação ao oscilante na amplitude de 0,34 cm foi de 96,44%, para amplitude de 0,88 cm foi de 93,23% e para amplitude de 1,22 cm foi de 91,65%. Para o IMRT direto a porcentagem de pontos aprovados do objeto estático em relação ao oscilante na amplitude de 0,34 cm foi de 98,42%, para amplitude de 0,88 cm foi de 95,66% e para amplitude de 1,22 cm foi de 94,31%. Para o IMRT inverso a porcentagem de pontos aprovados do objeto estático em relação ao oscilante na amplitude de 0,34 cm foi de 94,49%, para amplitude de 0,88 cm foi de 93,51% e para amplitude de 1,22 cm foi de 86,62%. A partir dos resultados, infere-se que a movimentação respiratória de baixa amplitude, para tratamentos de câncer de mama, não é um fator
preocupante para a rotina clínica, porém o aumento da amplitude da oscilação aumenta a inomogeneidade de dose e pode…
Advisors/Committee Members: Juliana Fernandes Pavoni, Gustavo Viani Arruda, Patrícia Nicolucci, Alessandra Tomal.
Subjects/Keywords: Dosimetria gel; Gel MAGIC-f; IMRT; Radioterapia 3D conformacional; Radioterapia de mama; Breast cancer radiotherapy; Conformational three-dimensional radiotherapy; Gel Dosimetry; IMRT; MAGIC-f gel
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Lizar, J. C. (2017). Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-30082017-152201/
Chicago Manual of Style (16th Edition):
Lizar, Jéssica Caroline. “Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório.” 2017. Masters Thesis, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-30082017-152201/.
MLA Handbook (7th Edition):
Lizar, Jéssica Caroline. “Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório.” 2017. Web. 11 Apr 2021.
Vancouver:
Lizar JC. Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório. [Internet] [Masters thesis]. University of São Paulo; 2017. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-30082017-152201/.
Council of Science Editors:
Lizar JC. Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório. [Masters Thesis]. University of São Paulo; 2017. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-30082017-152201/
21.
Ana Luiza Quevedo Ramos da Silva.
Avaliação de parâmetros dosimétricos de fontes de braquiterapia utilizando simulação Monte Carlo e dosimetria gel polimérica.
Degree: 2014, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-06102014-084506/
► A dosimetria em braquiterapia é importante para garantir a igualdade entre a dose entregue ao paciente e a dose planejada, porém a determinação experimental da…
(more)
▼ A dosimetria em braquiterapia é importante para garantir a igualdade entre a dose entregue ao paciente e a dose planejada, porém a determinação experimental da dose é difícil devido ao alto gradiente de dose em regiões próximas à fonte. Nesse sentido, a dosimetria gel polimérica têm sido estudada como forma de se obter a distribuição tridimensional das doses dessas fontes. O protocolo da Associação Americana de Físicos em Medicina, intitulado TG-43, propõe um formalismo para o cálculo de dose de fontes de braquiterapia através de parâmetros da atividade, anisotropia e geometria da fonte, além de atenuação e espalhamento da radiação produzida pela fonte. Porém, a determinação das funções dosimétricas necessárias para o cálculo da dose não é feita diretamente através de experimentos. Nessa linha, o Método Monte Carlo vêm sendo utilizado no cálculo dessas funções dosimétricas em braquiterapia. Neste trabalho, foram determinados os parâmetros
dosimétricos de duas fontes de braquiterapia, 60Co e 192Ir, utilizando simulação Monte Carlo com o código PENELOPE, assim como as distribuições de dose utilizando dosimetria gel polimérica com o MAGIC-f. Os dados obtidos computacionalmente foram comparados com a literatura, obtendo-se concordância melhor que 98% em todos os parâmetros para a fonte de 60Co. Para a fonte de 192Ir, encontraram-se diferenças de até 22%, embora quando os resultados deste trabalho foram comparados com o sistema de planejamento, o ajuste utilizado para o conjunto de pontos possui R2 de 0,9996. A comparação das distribuições de dose da fonte de 192Ir simuladas e determinadas com o gel polimérico MAGIC-f, apresentou concordância de 97% nos pontos englobados pela isodose de 50%, quando o critério de 3% e 3 mm foi utilizado. Esses resultados evidenciam o potencial do uso da dosimetria gel polimérica e da simulação Monte Carlo com o código PENELOPE em dosimetria de fontes de braquiterapia de alta taxa de dose.
Dosimetry in brachytherapy is important to assure the conformity between the planned and the delivered dose to the patient. However, the experimental determination of dose is difficult in this technique due the high dose gradient in regions near the source. Hence, polymer gel dosimetry has been studied as a tool to obtain three-dimensional distribution dose for these sources. A report of American Association of Medical Physics, entitled TG-43, proposes a formalism for dose calculation for brachytherapy sources through parameters such as activity, anisotropy and geometry of the source, and the attenuation and radiation scattering produced in the surrounding medium. However, the dosimetric functions needed for dose calculations are not directly determined through experiments. In this concern, the Monte Carlo method has been used in the calculation of these dosimetric funcions in brachytherapy. In the present work, the dosimetric parameters for two brachytherapy sources, 60Co e
192Ir, were determined using Monte Carlo simulation with PENELOPE code, and the dose distributions for the 192Ir…
Advisors/Committee Members: Patrícia Nicolucci, Carmen Sandra Guzmán Calcina, Alessandro Martins da Costa.
Subjects/Keywords: Braquiterapia; Código PENELOPE; Dosimetria em Braquiterapia; Gel MAGIC-f.; Brachytherapy; Dosimetry in Brachytherapy; MAGIC-f gel.; PENELOPE code
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Silva, A. L. Q. R. d. (2014). Avaliação de parâmetros dosimétricos de fontes de braquiterapia utilizando simulação Monte Carlo e dosimetria gel polimérica. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-06102014-084506/
Chicago Manual of Style (16th Edition):
Silva, Ana Luiza Quevedo Ramos da. “Avaliação de parâmetros dosimétricos de fontes de braquiterapia utilizando simulação Monte Carlo e dosimetria gel polimérica.” 2014. Masters Thesis, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-06102014-084506/.
MLA Handbook (7th Edition):
Silva, Ana Luiza Quevedo Ramos da. “Avaliação de parâmetros dosimétricos de fontes de braquiterapia utilizando simulação Monte Carlo e dosimetria gel polimérica.” 2014. Web. 11 Apr 2021.
Vancouver:
Silva ALQRd. Avaliação de parâmetros dosimétricos de fontes de braquiterapia utilizando simulação Monte Carlo e dosimetria gel polimérica. [Internet] [Masters thesis]. University of São Paulo; 2014. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-06102014-084506/.
Council of Science Editors:
Silva ALQRd. Avaliação de parâmetros dosimétricos de fontes de braquiterapia utilizando simulação Monte Carlo e dosimetria gel polimérica. [Masters Thesis]. University of São Paulo; 2014. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-06102014-084506/
22.
Marcelo Menna Barreto Schwarcke.
Caracterização do gel polimérico MAGIC-f para aplicação em medicina nuclear utilizando imagens de ressonância magnética.
Degree: 2013, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-12112013-084219/
► Este trabalho visa aprimorar e tornar mais precisa a utilização do dosímetro gel polimérico MAGIC-f no estudo da distribuição de dose para fonte radioativas utilizadas…
(more)
▼ Este trabalho visa aprimorar e tornar mais precisa a utilização do dosímetro gel polimérico MAGIC-f no estudo da distribuição de dose para fonte radioativas utilizadas na terapia e diagnóstico em medicina nuclear. Para isso foram avaliados os parâmetros de leitura do gel em equipamentos de ressonância magnética e sua resposta quando comparado a resultados obtidos através da utilização do código PENELOPE de simulação Monte Carlo. Dentre as incertezas observadas no processo global da utilização do gel MAGIC-f, sua manufatura foi a que demonstrou uma maior preocupação uma vez que erro na frações de componentes químicos adicionados ocasiona grande diferença na resposta do dosímetro. A aquisição da informação dosimétrica em um equipamento de imagem por ressonância magnética demonstrou que tempos ao eco mais curtos são mais eficientes na diferenciação do sinal gerado no processo de polimerização devido a utilização de fontes de medicina nuclear do que
ajustes na resolução da imagem e que a homogeneidade de campo magnético pode ocasionar grande alteração nos valores obtidos. Experimentos realizados com o gel MAGIC-f, demonstraram um baixa dependência energética e um grande dependência com a taxa de dose, dois fatores importantes em medicina, mas resultados simulados e experimentais comparativos utilizando fontes de I-131, Tc-99m e F-18, demonstraram uma grande precisão nos resultados apresentados, tornando assim o gel MAGIC-f uma excelente ferramenta na verificação volumétrica da dose absorvida na terapia com fontes de medicina nuclear.
This work aims to improve and make more accurate use of the gel dosimeter MAGIC-f polymer in the study of dose distribution for radioactive source used in therapy and diagnosis in nuclear medicine. For this, MRI parameters reading of the gel were evaluated and its response when compared to results obtained using a Monte Carlo simulation PENELOPE code. Among the uncertainties observed in the
overall use of MAGIC-f gel, its manufacturing demonstrated a greater concern since error in chemical fractions added causes big difference in the response of the dosimeter. The acquisition of dosimetric equipment information in a magnetic resonance imaging showed that the shorter eco times are more efficient in differentiating the signal generated in the polymerization process due to the use of sources of nuclear medicine than image resolution changes and the homogeneity of the magnetic field can cause large difference in the results. Experiments performed with the MAGIC-f gel, demonstrated a low energy dependence and a large dependence on the dose rate, two important factors in nuclear medicine, but comparative results with simulated and experimental processes using sources of I-131, Tc-99m and F-18 showed a great accuracy in results, thus making the MAGIC-f gel an excellent tool for volumetric verification of absorbed dose therapy with sources of nuclear medicine.
Advisors/Committee Members: Oswaldo Baffa Filho, Patrícia Nicolucci, Lauro Wichert Ana, Bernardo Maranhão Dantas, Patrícia Nicolucci, Ana Maria Marques da Silva.
Subjects/Keywords: Dosimetria Gel Polimérica; Medicina Nuclear; Simulação Monte Carlo; Monte Carlo Simulation; Nuclear Medicine; Polymer Gel Dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Schwarcke, M. M. B. (2013). Caracterização do gel polimérico MAGIC-f para aplicação em medicina nuclear utilizando imagens de ressonância magnética. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-12112013-084219/
Chicago Manual of Style (16th Edition):
Schwarcke, Marcelo Menna Barreto. “Caracterização do gel polimérico MAGIC-f para aplicação em medicina nuclear utilizando imagens de ressonância magnética.” 2013. Doctoral Dissertation, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-12112013-084219/.
MLA Handbook (7th Edition):
Schwarcke, Marcelo Menna Barreto. “Caracterização do gel polimérico MAGIC-f para aplicação em medicina nuclear utilizando imagens de ressonância magnética.” 2013. Web. 11 Apr 2021.
Vancouver:
Schwarcke MMB. Caracterização do gel polimérico MAGIC-f para aplicação em medicina nuclear utilizando imagens de ressonância magnética. [Internet] [Doctoral dissertation]. University of São Paulo; 2013. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-12112013-084219/.
Council of Science Editors:
Schwarcke MMB. Caracterização do gel polimérico MAGIC-f para aplicação em medicina nuclear utilizando imagens de ressonância magnética. [Doctoral Dissertation]. University of São Paulo; 2013. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-12112013-084219/
23.
Ana Luiza Quevedo Ramos da Silva.
Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia.
Degree: 2018, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-25012019-102410/
► A dosimetria em radioterapia é importante para garantir a igualdade entre a dose prescrita e a dose entregue ao paciente. Devido às inovações tecnológicas dos…
(more)
▼ A dosimetria em radioterapia é importante para garantir a igualdade entre a dose prescrita e a dose entregue ao paciente. Devido às inovações tecnológicas dos aparelhos de radioterapia e das técnicas de tratamento, aumentou-se a dose entregue nas regiões lesionadas. A dosimetria gel polimérica tem se mostrado promissora no controle da qualidade de fontes de radioterapia. O objetivo desse trabalho foi desenvolver um dosímetro gel, MAGIC-fm, para aplicações em dosimetria em Radioterapia e estudando características de sua resposta dosimétrica. O entendimento da construção da resposta dosimétrica, do processo de polimerização e da composição elementar do gel foi realizado através de imagem por ressonância magnética, em intensidades de campo magnético de 3T, 7T e 9,4T, com sequências de leitura de dispersão em T1, Espectroscopia Resolvida no Tempo, Pulse Size Ratio, Relaxometria em T2 e Efeito Overhauser Nuclear. Embora o dosímetro desenvolvido não
tenha apresentado dispersão em T1, com essa sequência foi possível determinar R1 e R2, que podem ser utilizados em dosimetria. Através das análises de espectroscopia, verificou-se a contribuição de cada elemento do gel na resposta dosimétrica. O aparecimento de efeitos NOE conforme o aumento da dose, mostrou-se promissora para detecção de dose em gel dosimétrico. O gel MAGIC-fm apresentou sensibilidade 40% maior que a formulação original do gel MAGIC-f, além de saturação de resposta acima de 50 Gy. Utilizando-se a técnica de relaxometria avaliou-se a dependência de resposta com a energia e a taxa de dose em feixes de fótons e elétrons tipicamente utilizados em tratamentos de radioterapia. O processo de calibração do dosímetro foi estudado, concluindo-se que o uso de objetos simuladores com tamanhos similares aqueles de interesse clínico devem ser usados. Uma aplicação de dosimetria em fonte de braquiterapia de alta taxa de dose de 192Ir foi realizada, com resultados comparados com
dados do sistema de planejamento. Os resultados apresentaram concordância em mais de 95% dos pontos das regiões analisadas, incluindo regiões de alta dose, concluindo-se que o gel desenvolvido, MAGIC-fm, é promissor no controle da qualidade de fontes de radioterapia
Dosimetry in radiotherapy is important to ensure equality between the prescribed dose and the delivered dose to the patient. Due to the technological innovations of the radiotherapy machines and the treatment techniques, increased the delivered dose in the injured regions. Polymer gel dosimetry has shown promising in the quality control of radiotherapy sources. The purpose of this work was to develop a dosimeter gel, MAGIC-fm, for applications in dosimetry in Radiotherapy and to study characteristics of its dosimetric response. The understanding of dosimetric response construction, the polymerization process and the gel elemental composition was performed by magnetic resonance imaging at magnetic field intensities of
3T, 7T and 9.4T, with reading sequences of T1 dispersion, Time-Resolved Spectroscopy, Pulse Size Ratio, T2…
Advisors/Committee Members: Patrícia Nicolucci, Luciano Bachmann, Carmen Sandra Guzmán Calcina, Paulo José Cecilio, Renata Ferranti Leoni, Marcelo Menna Barreto Schwarcke.
Subjects/Keywords: Dosimetria em radioterapia; Gel MAGIC-fm; Imagem de ressonância magnética; MAGIC-fm Gel; Magnetic resonance imaging; Radiotherapy dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Silva, A. L. Q. R. d. (2018). Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-25012019-102410/
Chicago Manual of Style (16th Edition):
Silva, Ana Luiza Quevedo Ramos da. “Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia.” 2018. Doctoral Dissertation, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-25012019-102410/.
MLA Handbook (7th Edition):
Silva, Ana Luiza Quevedo Ramos da. “Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia.” 2018. Web. 11 Apr 2021.
Vancouver:
Silva ALQRd. Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia. [Internet] [Doctoral dissertation]. University of São Paulo; 2018. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-25012019-102410/.
Council of Science Editors:
Silva ALQRd. Dosimetria gel polimérica usando imagem de ressonância magnética para aplicação em radioterapia. [Doctoral Dissertation]. University of São Paulo; 2018. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-25012019-102410/
24.
Diana Maritza Cuevas Rojas.
Dosimetria 3D de um tratamento simulado de próstata na presença de próteses femorais metálicas.
Degree: 2017, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-11072017-094424/
► Historicamente a radioterapia é divida em radioterapia externa, braquiterapia e radioisotopoterapia sistemática. As diferenças entre as três está no posicionamento da fonte de radiação com…
(more)
▼ Historicamente a radioterapia é divida em radioterapia externa, braquiterapia e radioisotopoterapia sistemática. As diferenças entre as três está no posicionamento da fonte de radiação com respeito ao corpo humano. Na radioterapia externa a fonte fica a uma certa distância do paciente, já no caso da braquiterapia as fontes podem ser inseridas dentro de cavidades do corpo ou implantadas diretamente nos tecidos. Na radioisotopoterapia sistemática isótopos radiativos são administrados por via oral ou venosa. Dessas três a radioterapia externa é a mais usada pois, ela permite realizar planejamentos de radioterapia em três dimensões (3D), partindo inicialmente de uma tomografia computadorizada da região do tumor. O planejamento baseado na tomografia computadorizada permite que a distribuição da radiação nos tecidos seja feito com mais precisão evitando assim, que os tecidos sadios sejam afetados. Nesse trabalho a radioterapia externa convencional, foi
implementada e executada para um tratamento de próstata com implantes metálicos, usando 4 campos de irradiação (0, 90, 180, 270 graus) e uma dose total planejada de 70 Gy fracionada em 35 sessões, cada uma com 2 Gy. Em qualquer tipo de tratamento que envolva a radiação ionizante é exigido um controle de qualidade para assim, determinar se a dose inicialmente planejada será entregue ou não ao tumor. Idealmente deveria ser implementado um controle de qualidade em três dimensões mas, até o momento não há um dosímetro 3D consolidado na rotina clinica. No entanto, o uso de géis poliméricos associados à técnica de leitura de dose com imagem de ressonância magnética (IRM) possibilita a dosimetria tridimensional. Nesse contexto, é aplicada a dosimetria 3D usando para isso, o gel magic com formaldeído (magic-f). Além da dosimetria 3D, foram realizadas medidas de dose absorvida por meio de dosimetria pontual, para tal fim são utilizados dosímetros termoluminescentes e de alanina. Na avaliação
da distribuição de dose feita pelo planejamento e a medida com o gel é usado a análise gama (3%/3mm), neste caso, a distribuição de dose medida concorda com a distribuição de dose planejada TPS. A análise gama apresenta um porcentagem de aprovação do 93%. Os valores de dose absorvida na interface osso-metal determinados pelos dosímetros TL apresentam um aumento de 1,73 Gy na região do osso sacro e outros aumentos entre o 0,16 e 0,33 Gy foram encontrados em regiões como a cabeça do fêmur e quadril. Esses aumentos na dose foram só para duas sessões com doses entregadas ao fantom de 2 Gy. De igual maneira para os dosímetros de alanina se encontro um aumento na dose de 1,22 e 2,42 Gy na região do osso sacro. O planejamento feito nesse caso foi de 6 Gy. Os resultados evidentemente mostram como as inomogeneidades de um material com número atómico alto, gera perturbações sobre as distribuições de dose inicialmente planejadas.
Historically, Radiotherapy is divided into external
radiotherapy, brachytherapy and systemic radioisotopotherapy. The difference between the three lies in the position…
Advisors/Committee Members: Oswaldo Baffa Filho, Gustavo Viani Arruda, Angela Mitie Otta Kinoshita, Patrícia Nicolucci.
Subjects/Keywords: dosimetria termoluminescente e dosimetria ESR com alanina.; gel magic-f; Radioterapia convencional; Conventional radiotherapy; magic- f gel; Thermoluminescent dosimetry and ESR dosimetry with alanine.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rojas, D. M. C. (2017). Dosimetria 3D de um tratamento simulado de próstata na presença de próteses femorais metálicas. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/59/59135/tde-11072017-094424/
Chicago Manual of Style (16th Edition):
Rojas, Diana Maritza Cuevas. “Dosimetria 3D de um tratamento simulado de próstata na presença de próteses femorais metálicas.” 2017. Masters Thesis, University of São Paulo. Accessed April 11, 2021.
http://www.teses.usp.br/teses/disponiveis/59/59135/tde-11072017-094424/.
MLA Handbook (7th Edition):
Rojas, Diana Maritza Cuevas. “Dosimetria 3D de um tratamento simulado de próstata na presença de próteses femorais metálicas.” 2017. Web. 11 Apr 2021.
Vancouver:
Rojas DMC. Dosimetria 3D de um tratamento simulado de próstata na presença de próteses femorais metálicas. [Internet] [Masters thesis]. University of São Paulo; 2017. [cited 2021 Apr 11].
Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-11072017-094424/.
Council of Science Editors:
Rojas DMC. Dosimetria 3D de um tratamento simulado de próstata na presença de próteses femorais metálicas. [Masters Thesis]. University of São Paulo; 2017. Available from: http://www.teses.usp.br/teses/disponiveis/59/59135/tde-11072017-094424/
University of Lund
25.
Nordström, Fredrik.
Quality Assurance in Radiotherapy - Development and
evaluation of new tools for improved patient safety.
Degree: 2012, University of Lund
URL: https://lup.lub.lu.se/record/2493127
;
https://portal.research.lu.se/ws/files/5843929/2493135.pdf
► Preparation for radiotherapy is a complex procedure that involves many different technologies and groups of professionals. The rapid development and introduction of new technologies throughout…
(more)
▼ Preparation for radiotherapy is a complex procedure
that involves many different technologies and groups of
professionals. The rapid development and introduction of new
technologies throughout the last decade have made it possible to
deliver highly conformal, individually-shaped dose distributions
with high accuracy. However, there is widespread concern that
current quality assurance practices have not been updated at the
pace necessary to provide adequate and cost-effective safeguards
against treatment delivery errors. The overall aim of this thesis
was to develop and evaluate new, efficient tools for
patient-specific quality assurance of the radiotherapy process,
including the following areas: transfer of information, independent
monitor unit verification, pre-treatment measurements, in vivo
dosimetry, and end-to-end tests. Within the framework of the
thesis, a concept for ensuring data integrity was proposed and used
to compare different combinations of treatment planning systems and
record-and-verify systems with respect to data integrity. Because
the concept is based on the Digital Imaging and Communications in
Medicine (DICOM) global information standard, it is generally
applicable to most radiotherapy computer systems. Additionally, a
software for monitor unit verifications was developed, and the
tools within Statistical Process Control were used to analyse
calculation results from this software in a multicentre study.
Time-resolved dosimetry systems were developed and applied to
pre-treatment measurements and in vivo dosimetry, allowing rigorous
analysis of the accuracy of the treatment planning and delivery
systems and forming a basis for real-time in vivo dosimetry.
Finally, gel dosimetry and anthropomorphic phantoms were
demonstrated to provide important tools for complete end-to-end
tests. The tools developed in this thesis have two important
applications: routine use in daily clinical practice, and when
introducing new technologies in the local clinical setting. The
proposed methods and concepts can improve patient safety and reduce
the resources required for a comprehensive quality assurance
program.
Subjects/Keywords: Radiology, Nuclear Medicine and Medical
Imaging; monitor unit verification; in vivo dosimetry; real-time verification; gel dosimetry; 4D dosimetry; IMRT; VMAT; data integrity; radiotherapy; Quality assurance
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Nordström, F. (2012). Quality Assurance in Radiotherapy - Development and
evaluation of new tools for improved patient safety. (Doctoral Dissertation). University of Lund. Retrieved from https://lup.lub.lu.se/record/2493127 ; https://portal.research.lu.se/ws/files/5843929/2493135.pdf
Chicago Manual of Style (16th Edition):
Nordström, Fredrik. “Quality Assurance in Radiotherapy - Development and
evaluation of new tools for improved patient safety.” 2012. Doctoral Dissertation, University of Lund. Accessed April 11, 2021.
https://lup.lub.lu.se/record/2493127 ; https://portal.research.lu.se/ws/files/5843929/2493135.pdf.
MLA Handbook (7th Edition):
Nordström, Fredrik. “Quality Assurance in Radiotherapy - Development and
evaluation of new tools for improved patient safety.” 2012. Web. 11 Apr 2021.
Vancouver:
Nordström F. Quality Assurance in Radiotherapy - Development and
evaluation of new tools for improved patient safety. [Internet] [Doctoral dissertation]. University of Lund; 2012. [cited 2021 Apr 11].
Available from: https://lup.lub.lu.se/record/2493127 ; https://portal.research.lu.se/ws/files/5843929/2493135.pdf.
Council of Science Editors:
Nordström F. Quality Assurance in Radiotherapy - Development and
evaluation of new tools for improved patient safety. [Doctoral Dissertation]. University of Lund; 2012. Available from: https://lup.lub.lu.se/record/2493127 ; https://portal.research.lu.se/ws/files/5843929/2493135.pdf
Vanderbilt University
26.
Whitney, Heather Marie.
Studies of the design, use, and characteristics of methacrylic acid-based polymer gel dosimeters.
Degree: PhD, Physics, 2009, Vanderbilt University
URL: http://hdl.handle.net/1803/10517
► Polymer gel dosimeters are three-dimensional radiation-sensitive materials comprised of monomers and other chemicals distributed in an aqueous gelatin matrix. Upon irradiation by high energy X…
(more)
▼ Polymer
gel dosimeters are three-dimensional radiation-sensitive materials comprised of monomers and other chemicals distributed in an aqueous gelatin matrix. Upon irradiation by high energy X or gamma rays, free radicals formed within the water initiate polymerization of the monomers, resulting in distributions of polymer that reflect the distribution of radiation dose. The polymers in turn affect the local nuclear magnetic resonance (NMR) properties of water, so that complex, integrated radiation dose distributions can be measured with high spatial resolution using magnetic resonance imaging. Previous studies have demonstrated the use of polymer gels for applications in
dosimetry for clinical radiation therapy. However, there are several aspects of polymer
gel dosimetry that remain unresolved. In this thesis some of these problems are addressed. In particular, the design and composition of gels for optimal dose response, the characterization of their dose responses for different NMR properties, the development of improved imaging methods, and the underlying mechanisms of dose response, are each considered. Methacrylic acid-based dosimeters have been optimized for measurements of dose based on transverse relaxation rates. In addition, measurements of other NMR parameters, such as the rates that govern magnetization transfer, are made, are considered and a new magnetization transfer parameter, the magnetization transfer proportion, is introduced as a simplified measure of dose response that is less susceptible to imaging errors than more traditional measures. A simple model is introduced to explain the dose response in terms of an increase in the number of efficiently relaxing protons through a chemical exchange relaxation mechanism, and the parameters of this model are derived from a series of appropriate NMR experiments.
Advisors/Committee Members: Todd E. Peterson (committee member), Richard F. Haglund (committee member), Daniel F. Gochberg (committee member), Malcolm J. Avison (committee member), John C. Gore (Committee Chair).
Subjects/Keywords: magnetic resonance imaging; polymer gel dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Whitney, H. M. (2009). Studies of the design, use, and characteristics of methacrylic acid-based polymer gel dosimeters. (Doctoral Dissertation). Vanderbilt University. Retrieved from http://hdl.handle.net/1803/10517
Chicago Manual of Style (16th Edition):
Whitney, Heather Marie. “Studies of the design, use, and characteristics of methacrylic acid-based polymer gel dosimeters.” 2009. Doctoral Dissertation, Vanderbilt University. Accessed April 11, 2021.
http://hdl.handle.net/1803/10517.
MLA Handbook (7th Edition):
Whitney, Heather Marie. “Studies of the design, use, and characteristics of methacrylic acid-based polymer gel dosimeters.” 2009. Web. 11 Apr 2021.
Vancouver:
Whitney HM. Studies of the design, use, and characteristics of methacrylic acid-based polymer gel dosimeters. [Internet] [Doctoral dissertation]. Vanderbilt University; 2009. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/1803/10517.
Council of Science Editors:
Whitney HM. Studies of the design, use, and characteristics of methacrylic acid-based polymer gel dosimeters. [Doctoral Dissertation]. Vanderbilt University; 2009. Available from: http://hdl.handle.net/1803/10517
Queensland University of Technology
27.
Khoei, Shadi.
Quantitative ultrasound computed tomography imaging of PAGAT radiation dosimetry gel.
Degree: 2013, Queensland University of Technology
URL: https://eprints.qut.edu.au/63958/
► This research developed and scientifically validated a new ultrasound transmission computed tomography system with the aim of quantitative assessment of a polymer gel dosimeter including…
(more)
▼ This research developed and scientifically validated a new ultrasound transmission computed tomography system with the aim of quantitative assessment of a polymer gel dosimeter including dose response verification of ultrasonic parameters of attenuation, velocity and broadband ultrasound attenuation (BUA). This work was the first to investigate and report ultrasound frequency dependent attenuation in a gel dosimeter, demonstrating a dose dependence.
Subjects/Keywords: Ultrasound computed tomography; Ultrasound attenuation; Broadband ultrasound attenuation; Ultrasound imaging; Polymer gel dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Khoei, S. (2013). Quantitative ultrasound computed tomography imaging of PAGAT radiation dosimetry gel. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/63958/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Khoei, Shadi. “Quantitative ultrasound computed tomography imaging of PAGAT radiation dosimetry gel.” 2013. Thesis, Queensland University of Technology. Accessed April 11, 2021.
https://eprints.qut.edu.au/63958/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Khoei, Shadi. “Quantitative ultrasound computed tomography imaging of PAGAT radiation dosimetry gel.” 2013. Web. 11 Apr 2021.
Vancouver:
Khoei S. Quantitative ultrasound computed tomography imaging of PAGAT radiation dosimetry gel. [Internet] [Thesis]. Queensland University of Technology; 2013. [cited 2021 Apr 11].
Available from: https://eprints.qut.edu.au/63958/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Khoei S. Quantitative ultrasound computed tomography imaging of PAGAT radiation dosimetry gel. [Thesis]. Queensland University of Technology; 2013. Available from: https://eprints.qut.edu.au/63958/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Wright State University
28.
Courter, Erik Joseph-Leonard.
Use of ClearView Gel Dosimeter for Quality Assurance and
Testing of Stereotactic Radiosurgery.
Degree: MS, Physics, 2016, Wright State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=wright1466417256
► There exists a lack of accurate, reproducible three-dimensional dosimetry techniques for stereotactic radiosurgery (SRS) commissioning and quality assurance. This experiment evaluates the use of ClearView…
(more)
▼ There exists a lack of accurate, reproducible
three-dimensional
dosimetry techniques for stereotactic
radiosurgery (SRS) commissioning and quality assurance. This
experiment evaluates the use of ClearView
gel dosimeters as an
alternative to current methods for small field
dosimetry in SRS
testing. ClearView differs from other
gel dosimeters in that it
uses tetrazolium salt in its chemical make-up in place of
traditional Fricke-type compounds. Using a Varian TrueBeam
radiotherapy system to deliver the radiation, three vials of
ClearView
gel dosimeter were tested in three different dose
delivery scenarios. The first test examined the dosimeter’s
response to a static beam with the dose isocenter targeted to the
centroid of the vial. The second evaluation consisted of a full
rotational SRS delivery about the center of the dosimeter. Lastly,
a complete end-to-end treatment plan was performed to evaluate the
accuracy of the dosimeter in a full SRS procedure. The three
dosimeters were then scanned to measure the dose distribution
throughout the
gel. Finally, the resulting data was compared to the
initial treatment plan to determine the accuracy of the
gel.
According to the comparisons performed, the ClearView
gel showed
capability of sub-millimeter spatial accuracy across the three
evaluations, with a maximum geometric uncertainty of 1.2 mm. Based
on these results, ClearView
gel shows promise for possible use in
SRS
dosimetry applications in clinical settings.
Advisors/Committee Members: Gossman, Michael (Advisor), Foy, Brent (Advisor).
Subjects/Keywords: Physics; ClearView; gel dosimeter; stereotactic radiosurgery; SRS; quality assurance; small field dosimetry
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Courter, E. J. (2016). Use of ClearView Gel Dosimeter for Quality Assurance and
Testing of Stereotactic Radiosurgery. (Masters Thesis). Wright State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=wright1466417256
Chicago Manual of Style (16th Edition):
Courter, Erik Joseph-Leonard. “Use of ClearView Gel Dosimeter for Quality Assurance and
Testing of Stereotactic Radiosurgery.” 2016. Masters Thesis, Wright State University. Accessed April 11, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=wright1466417256.
MLA Handbook (7th Edition):
Courter, Erik Joseph-Leonard. “Use of ClearView Gel Dosimeter for Quality Assurance and
Testing of Stereotactic Radiosurgery.” 2016. Web. 11 Apr 2021.
Vancouver:
Courter EJ. Use of ClearView Gel Dosimeter for Quality Assurance and
Testing of Stereotactic Radiosurgery. [Internet] [Masters thesis]. Wright State University; 2016. [cited 2021 Apr 11].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=wright1466417256.
Council of Science Editors:
Courter EJ. Use of ClearView Gel Dosimeter for Quality Assurance and
Testing of Stereotactic Radiosurgery. [Masters Thesis]. Wright State University; 2016. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=wright1466417256
Queens University
29.
Alexander, Kevin.
End-to-End Quality Assurance of Complex Radiation Therapy Treatments
.
Degree: Physics, Engineering Physics and Astronomy, Queens University
URL: http://hdl.handle.net/1974/27547
► Radiation treatments have become increasingly complex, making quality assurance (QA) of radiation therapy deliveries of vital importance. In order to measure complex dose deliveries, it…
(more)
▼ Radiation treatments have become increasingly complex, making quality assurance (QA) of radiation therapy deliveries of vital importance. In order to measure complex dose deliveries, it is crucial to have the proper dosimetric, readout, and analysis tools that can accurately report the delivered dose. While clinics generally perform a wide array of quality assurance testing on specific steps of the planning and delivery of the radiation, they seldom perform routine end-to-end testing of the entire treatment planning and delivery process. Such end-to-end tests are a valuable QA tool to help ensure that all individual components are working together to deliver the planned dose. Using an anthropomorphic phantom that incorporates several dosimeters (with fiducials for localization) for end-to-end QA can help to mimic a patient treatment and to study the overall geometric and dosimetric accuracy of an entire treatment process.
In this thesis, we look to perform comprehensive end-to-end quality assurance of radiation therapy treatments using point detectors, and two-dimensional (2D) and 3D dosimeters. Specifically, this work examines: (i) improving film dosimetry readout methods by testing the capabilities of our inhouse diffuse light field and camera film imaging system, as well as developing a new point source film scanner to eliminate stray light issues present in the diffuse light system, (ii) developing a streamlined gel dosimetry workflow and validating new gel dosimetry analysis software, (iii) using multiple dosimeters, coupled with commercial and in-house developed phantoms, to inform and verify clinical protocols and to commission new treatment
techniques, (iv) characterizing and benchmarking various 3D printing materials (for applications in 3D printed patient bolus and custom phantom manufacturing), (v) and developing an anthropomorphic head phantom that accommodates multiple dosimeters, using it to test a complete clinical treatment process from beginning to end (exactly like an actual patient would be treated), and involving clinical staff at each step of the process.
Subjects/Keywords: Film Dosimetry
;
Radiation Therapy
;
Gel Dosimetry
;
End-to-End Quality Assurance
;
3D Printing
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Alexander, K. (n.d.). End-to-End Quality Assurance of Complex Radiation Therapy Treatments
. (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/27547
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Alexander, Kevin. “End-to-End Quality Assurance of Complex Radiation Therapy Treatments
.” Thesis, Queens University. Accessed April 11, 2021.
http://hdl.handle.net/1974/27547.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Alexander, Kevin. “End-to-End Quality Assurance of Complex Radiation Therapy Treatments
.” Web. 11 Apr 2021.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Vancouver:
Alexander K. End-to-End Quality Assurance of Complex Radiation Therapy Treatments
. [Internet] [Thesis]. Queens University; [cited 2021 Apr 11].
Available from: http://hdl.handle.net/1974/27547.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.
Council of Science Editors:
Alexander K. End-to-End Quality Assurance of Complex Radiation Therapy Treatments
. [Thesis]. Queens University; Available from: http://hdl.handle.net/1974/27547
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.
Queensland University of Technology
30.
Poole, Christopher Mark.
Faster Monte Carlo simulation of radiotherapy geometries.
Degree: 2012, Queensland University of Technology
URL: https://eprints.qut.edu.au/59972/
► Using Monte Carlo simulation for radiotherapy dose calculation can provide more accurate results when compared to the analytical methods usually found in modern treatment planning…
(more)
▼ Using Monte Carlo simulation for radiotherapy dose calculation can provide more accurate results when compared to the analytical methods usually found in modern treatment planning systems, especially in regions with a high degree of inhomogeneity.
These more accurate results acquired using Monte Carlo simulation however, often require orders of magnitude more calculation time so as to attain high precision, thereby reducing its utility within the clinical environment. This work aims to improve the utility of Monte Carlo simulation within the clinical environment by developing techniques which enable faster Monte Carlo simulation of radiotherapy geometries. This is achieved principally through the use new high performance computing environments and simpler alternative, yet equivalent representations of complex geometries.
Firstly the use of cloud computing technology and it application to radiotherapy dose calculation is demonstrated. As with other super-computer like environments, the time to complete a simulation decreases as 1=n with increasing n cloud based computers performing the calculation in parallel. Unlike traditional super computer infrastructure however, there is no initial outlay of cost, only modest ongoing usage fees; the simulations described in the following are performed using this cloud computing technology. The definition of geometry within the chosen Monte Carlo simulation environment - Geometry & Tracking 4 (GEANT4) in this case - is also addressed in this work. At the simulation implementation level, a new computer aided design interface is presented for use with GEANT4 enabling direct coupling between manufactured parts and their equivalent in the simulation environment, which is of particular importance when defining linear accelerator treatment head geometry. Further, a new technique for navigating tessellated or meshed geometries is described, allowing for up to 3 orders of magnitude performance improvement with the use of tetrahedral meshes in place of complex triangular surface meshes. The technique has application in the definition of both mechanical parts in a geometry as well as patient geometry.
Static patient CT datasets like those found in typical radiotherapy treatment plans are often very large and present a significant performance penalty on a Monte Carlo simulation. By extracting the regions of interest in a radiotherapy treatment plan, and representing them in a mesh based form similar to those used in computer aided design, the above mentioned optimisation techniques can be used so as to reduce the time required to navigation the patient geometry in the simulation environment. Results presented in this work show that these equivalent yet much simplified patient geometry representations enable significant performance improvements over simulations that consider raw CT datasets alone.
Furthermore, this mesh based representation allows for direct manipulation of the geometry enabling motion augmentation for time dependant dose calculation for example. Finally, an…
Subjects/Keywords: CAD; DICOM; DICOM-RT; dosimetry; GEANT4; gel dosimetry; Monte Carlo; cloud computing; compute aided design; organic plastic scintillator; parallel computing; patient geometry; radiation transport; radiotherapy; treatment planning
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Poole, C. M. (2012). Faster Monte Carlo simulation of radiotherapy geometries. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/59972/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Poole, Christopher Mark. “Faster Monte Carlo simulation of radiotherapy geometries.” 2012. Thesis, Queensland University of Technology. Accessed April 11, 2021.
https://eprints.qut.edu.au/59972/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Poole, Christopher Mark. “Faster Monte Carlo simulation of radiotherapy geometries.” 2012. Web. 11 Apr 2021.
Vancouver:
Poole CM. Faster Monte Carlo simulation of radiotherapy geometries. [Internet] [Thesis]. Queensland University of Technology; 2012. [cited 2021 Apr 11].
Available from: https://eprints.qut.edu.au/59972/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Poole CM. Faster Monte Carlo simulation of radiotherapy geometries. [Thesis]. Queensland University of Technology; 2012. Available from: https://eprints.qut.edu.au/59972/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
◁ [1] [2] [3] ▶
. 
Open Access Theses and Dissertations