Combining Monte Carlo simulations and detector measurements for a novel quality assurance system of assembled brachytherapy eye plaques.
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Möehle, Swantje D.
issued: 2021-01-06T19:00:24Z
issued: 2020
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Quality assurance of radiation therapy devices used to treat cancer is important to assure successful treatment and prevent over- or under-dosage. For brachytherapy eye plaques, the current standard procedure involves measuring the individual seed air-kerma strengths in a well chamber and visually inspecting the plaque. This leaves room for errors to occur between seed verification, plaque assembly, and implantation. In addition, the availability of manufacturer-assembled commercial eye plaques has increased, where independent, pre-implantation verification is limited to verifying the seed strength of additional loose seeds from the same seed lot. Currently, no commercially available system or technique exists for routine quality assurance of assembled eye plaques. This thesis investigates whether a flat panel image detector can be used in combination with Monte Carlo simulations, to develop a quality assurance system for assembled I-125 and Pd-103 brachytherapy eye plaques. The detector is used in conjunction with an acrylic plaque holder to record the 2D dose distribution of the plaque perpendicular to the plaque central axis. The system is simulated in Monte Carlo to generate a 3D dose distribution. Calibrating the detector relative to the Monte Carlo results allows comparisons between simulated and measured plaques, making it possible to verify the central dose rate of the plaque and to verify the 2D dose distribution in the detector plane using gamma index analysis. Results showed good agreement between the dose distributions and central strengths of detector measured and simulated results for a variety of seed strengths and seed arrangements, enabling the detection of dead or missing seeds. A procedure was established to compare the results to TG-43 dose calculations used in treatment planning. The method was tested on BC Cancer in-house design acrylic eye plaques and a commercial Eye Physics dummy plaque. The detector showed strong attenuation for incoming ra…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/76967
note: Combining Monte Carlo Simulations and DetectorMeasurements for a Novel Quality Assurance System ofAssembled Brachytherapy Eye Plaques.bySwantje D. Mo¨hleA THESIS SUBMITTED IN PARTIAL FULFILLMENTOF THE REQUIREMENTS FOR THE DEGREE OFMaster of ScienceinTHE FACULTY OF GRADUATE AND POSTDOCTORALSTUDIES(Physics)The University of British Columbia(Vancouver)December 2020c© Swantje D. Mo¨hle, 2020The following individuals certify that they have read, and recommend to the Fac-ulty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled:Combining Monte Carlo Simulations and Detector Measurements fora Novel Quality Assurance System of Assembled Brachytherapy EyePlaques.submitted by Swantje D. Mo¨hle in partial fulfillment of the requirements for thedegree of Master of Science in Physics.Examining Committee:Ingrid Spadinger, Department of Surgery, Faculty of MedicineSupervisorI. Antoniu Popescu, Department of Physics and Astronomy, Faculty of ScienceAdditional ExamineriiAbstractQuality assurance of radiation therapy devices used to treat cancer is important toassure successful treatment and prevent over- or under-dosage. For brachyther-apy eye plaques, the current standard procedure involves measuring the individualseed air-kerma strengths in a well chamber and visually inspecting the plaque. Thisleaves room for errors to occur between seed verification, plaque assembly, and im-plantation. In addition, the availability of manufacturer-assembled commercial eyeplaques has increased, where independent, pre-implantation verification is limitedto verifying the seed strength of additional loose seeds from the same seed lot.Currently, no commercially available system or technique exists for routinequality assurance of assembled eye plaques. This thesis investigates whether a flatpanel image detector can be used in combination with Monte Carlo simulations, todevelop a quality assurance system for assembled I-125 and Pd-103 brachytherapyeye plaques. The detector is used i…
has type: Thesis/Dissertation
date issued: 2021-05
is shown at: 10.14288/1.0395483
language: eng
degree discipline: Physics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/76967