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Title: SU-F-T-122: 4Dand 5D Proton Dose Evaluation with Monte Carlo

Abstract

Purpose: We evaluated uncertainties in therapeutic proton doses of a lung treatment, taking into account intra-fractional geometry changes, such as breathing, and inter-fractional changes, such as tumor shrinkage and weight loss. Methods: A Monte Carlo study was performed using four dimensional CT image sets (4DCTs) and weekly repeat imaging (5DCTs) to compute fixed RBE (1.1) and variable RBE weighted dose in an actual lung treatment geometry. The MC2 Monte Carlo system was employed to simulate proton energy deposition and LET distributions according to a thoracic cancer treatment plan developed with a 3D-CT in a commercial treatment planning system, as well as in each of the phases of 4DCT sets which were recorded weekly throughout the course of the treatment. A cumulative dose distribution in relevant structures was computed and compared to the predictions of the treatment planning system. Results: Using the Monte Carlo method, dose deposition estimates with the lowest possible uncertainties were produced. Comparison with treatment planning predictions indicates that significant uncertainties may be associated with therapeutic lung dose prediction from treatment planning systems, depending on the magnitude of inter- and intra-fractional geometry changes. Conclusion: As this is just a case study, a more systematic investigation accounting for amore » cohort of patients is warranted; however, this is less practical because Monte Carlo simulations of such cases require enormous computational resources. Hence our study and any future case studies may serve as validation/benchmarking data for faster dose prediction engines, such as the track repeating algorithm, FDC.« less

Authors:
; ; ; ; ; ;  [1]
  1. UT MD Anderson Cancer Center, Houston, TX (United States)
Publication Date:
OSTI Identifier:
22642363
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BIOMEDICAL RADIOGRAPHY; COMPUTERIZED SIMULATION; COMPUTERIZED TOMOGRAPHY; FORECASTING; GEOMETRY; LUNGS; MONTE CARLO METHOD; PLANNING; RADIATION DOSE DISTRIBUTIONS

Citation Formats

Titt, U, Mirkovic, D, Yepes, P, Liu, A, Peeler, C, Randenyia, S, and Mohan, R. SU-F-T-122: 4Dand 5D Proton Dose Evaluation with Monte Carlo. United States: N. p., 2016. Web. doi:10.1118/1.4956258.
Titt, U, Mirkovic, D, Yepes, P, Liu, A, Peeler, C, Randenyia, S, & Mohan, R. SU-F-T-122: 4Dand 5D Proton Dose Evaluation with Monte Carlo. United States. doi:10.1118/1.4956258.
Titt, U, Mirkovic, D, Yepes, P, Liu, A, Peeler, C, Randenyia, S, and Mohan, R. Wed . "SU-F-T-122: 4Dand 5D Proton Dose Evaluation with Monte Carlo". United States. doi:10.1118/1.4956258.
@article{osti_22642363,
title = {SU-F-T-122: 4Dand 5D Proton Dose Evaluation with Monte Carlo},
author = {Titt, U and Mirkovic, D and Yepes, P and Liu, A and Peeler, C and Randenyia, S and Mohan, R},
abstractNote = {Purpose: We evaluated uncertainties in therapeutic proton doses of a lung treatment, taking into account intra-fractional geometry changes, such as breathing, and inter-fractional changes, such as tumor shrinkage and weight loss. Methods: A Monte Carlo study was performed using four dimensional CT image sets (4DCTs) and weekly repeat imaging (5DCTs) to compute fixed RBE (1.1) and variable RBE weighted dose in an actual lung treatment geometry. The MC2 Monte Carlo system was employed to simulate proton energy deposition and LET distributions according to a thoracic cancer treatment plan developed with a 3D-CT in a commercial treatment planning system, as well as in each of the phases of 4DCT sets which were recorded weekly throughout the course of the treatment. A cumulative dose distribution in relevant structures was computed and compared to the predictions of the treatment planning system. Results: Using the Monte Carlo method, dose deposition estimates with the lowest possible uncertainties were produced. Comparison with treatment planning predictions indicates that significant uncertainties may be associated with therapeutic lung dose prediction from treatment planning systems, depending on the magnitude of inter- and intra-fractional geometry changes. Conclusion: As this is just a case study, a more systematic investigation accounting for a cohort of patients is warranted; however, this is less practical because Monte Carlo simulations of such cases require enormous computational resources. Hence our study and any future case studies may serve as validation/benchmarking data for faster dose prediction engines, such as the track repeating algorithm, FDC.},
doi = {10.1118/1.4956258},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}