Investigation of a Monte Carlo model based dose calculation for Pd-103 low dose rate breast brachytherapy and I-125 low dose rate prostate brachytherapy
department or school: Science, Irving K. Barber Faculty of (Okanagan)
department or school: Computer Science, Mathematics, Physics and Statistics, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: McKeown, Dakota
issued: 2023-09-07T15:47:13Z
issued: 2023
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Purpose: Clinical brachytherapy is typically performed using TG43 formalism, which assumes a homogeneous water medium and does not account for factors such as interseed attenuation or tissue inhomogeneities. Monte Carlo (MC) model-based dose calculation algorithms (MBDCA) provide improved dosimetric accuracy. The purpose of this work was to quantify the impact of eb_gui, a Canadian developed, user-friendly MC MBDCA, on plan evaluation with 80 low dose rate (LDR) breast brachytherapy patients and 76 LDR prostate brachytherapy patients. Methods: Dosimetry of 80 breast brachytherapy cases treated with Pd-103 seeds (TheraSeed200, 2.3-2.8 U, 90 Gy prescription dose) and 76 prostate cases treated with I-125 seeds (AgX100, 0.354-0.493 U, 144 or 110 Gy prescription doses) were simulated using the MC program and doses were calculated using two methods: 1) water-equivalent MC and 2) material-assigned MC. The clinical dose-volume histogram metrics of the targets and organs at risk (OAR) for both simulations were extracted and compared across the two patient cohorts. Results: Breast target volumes showed a slight overestimation of dose by water-equivalent MC of 1% for the CTV V₁₀₀ and 6% for the ETV V₁₀₀ compared to the median material-assigned MC results (p < 0.05). Water-equivalent MC significantly underestimated the skin D₀ꓸ₂꜀ₘ₃ by 20.3% compared to material-assigned MC (p < 0.05). In prostate patients, water-equivalent MC overestimated CTV V₁₀₀ by 4.4% compared to material-assigned MC (p < 0.05). The only potentially clinical significant result for a prostate OAR is the urethra D₁꜀ₘ₃ , where dose was overestimated by 6.3% by water-equivalent MC (p < 0.05). Conclusion: MC simulation of 80 breast and 76 prostate LDR patients were performed. Slight overestimation of dose in target volumes and prostate OARs and potentially clinically significant underestimation of dose in skin were seen using the standard TG43 calculations when compared to the more accurate MBDCA. These differe…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/85815
note: INVESTIGATION OF A MONTE CARLO MODEL BASED DOSE CALCULATION FORPD-103 LOW DOSE RATE BREAST BRACHYTHERAPY AND I-125 LOW DOSE RATEPROSTATE BRACHYTHERAPYbyDakota McKeownA THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THEDEGREE OFMASTER OF SCIENCEinTHE COLLEGE OF GRADUATE STUDIES(Medical Physics)THE UNIVERSITY OF BRITISH COLUMBIA(Okanagan)September 2023© Dakota McKeown 2023The following individuals certify that they have read, and recommend to the College of GraduateStudies for acceptance, a thesis/dissertation entitled:INVESTIGATION OF A MONTE CARLO MODEL BASED DOSE CALCULATION FORPD-103 LOW DOSE RATE BREAST BRACHYTHERAPY AND I-125 LOW DOSE RATEPROSTATE BRACHYTHERAPYsubmitted by Dakota McKeown in partial fulfillment of the requirements of the degree of Masterof Science in Medical Physics.Dr. Chistina Haston - Department of Computer Science, Mathematics, Physics and Statistics, TheUniversity of British Columbia – OkanaganSupervisorDr. Yiwen Xu - Department of Medical Physics, BC Cancer – KelownaCo-SupervisorDr. Eric Wright - Department of Medical Physics, BC Cancer – KelownaSupervisory Committee MemberDr. Jeffrey Andrews - Department of Computer Science, Mathematics, Physics and Statistics, TheUniversity of British Columbia – OkanaganSupervisory Committee MemberDr. Elizabeth Huynh - Department of Oncology and Department of Medical Biophysics, WesternUniversityExternal ExamineriiAbstractPurpose: Clinical brachytherapy is typically performed using TG43 formalism, which as-sumes a homogeneous water medium and does not account for factors such as interseed atten-uation or tissue inhomogeneities. Monte Carlo (MC) model-based dose calculation algorithms(MBDCA) provide improved dosimetric accuracy. The purpose of this work was to quantify theimpact of eb_gui, a Canadian developed, user-friendly MC MBDCA, on plan evaluation with 80low dose rate (LDR) breast brachytherapy patients and 76 LDR prostate brachytherapy patients.Methods: Dosimetry of 80 breast brachy…
has type: Thesis/Dissertation
date issued: 2023-09
is shown at: 10.14288/1.0435775
language: eng
degree discipline: Medical 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
contributor: Haston, Christina
contributor: Xu, Yiwen
type: Text
type: Still Image
identifier URI: http://hdl.handle.net/2429/85815