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Title: SU-E-T-644: QuAArC: A 3D VMAT QA System Based On Radiochromic Film and Monte Carlo Simulation of Log Files

Abstract

Purpose: VMAT involves two main sources of uncertainty: one related to the dose calculation accuracy, and the other linked to the continuous delivery of a discrete calculation. The purpose of this work is to present QuAArC, an alternative VMAT QA system to control and potentially reduce these uncertainties. Methods: An automated MC simulation of log files, recorded during VMAT treatment plans delivery, was implemented in order to simulate the actual treatment parameters. The linac head models and the phase-space data of each Control Point (CP) were simulated using the EGSnrc/BEAMnrc MC code, and the corresponding dose calculation was carried out by means of BEAMDOSE, a DOSXYZnrc code modification. A cylindrical phantom was specifically designed to host films rolled up at different radial distances from the isocenter, for a 3D and continuous dosimetric verification. It also allows axial and/or coronal films and point measurements with several types of ion chambers at different locations. Specific software was developed in MATLAB in order to process and evaluate the dosimetric measurements, which incorporates the analysis of dose distributions, profiles, dose difference maps, and 2D/3D gamma index. It is also possible to obtain the experimental DVH reconstructed on the patient CT, by an optimization methodmore » to find the individual contribution corresponding to each CP on the film, taking into account the total measured dose, and the corresponding CP dose calculated by MC. Results: The QuAArC system showed high reproducibility of measurements, and consistency with the results obtained with the commercial system implemented in the verification of the evaluated treatment plans. Conclusion: A VMAT QA system based on MC simulation and high resolution dosimetry with film has been developed for treatment verification. It shows to be useful for the study of the real VMAT capabilities, and also for linac commissioning and evaluation of other verification devices.« less

Authors:
; ; ; ;  [1];  [2]; ;  [3]
  1. Universidad de Sevilla, Departamento de Fisiologia Medica y Biofisica, Seville (Spain)
  2. Hospital Infanta Luisa, Servicio de Radiofisica, Seville (Spain)
  3. Hospital Universitario Virgen del Rocio, Servicio de Radiofisica, Seville (Spain)
Publication Date:
OSTI Identifier:
22538153
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; COMPUTER CODES; COMPUTERIZED SIMULATION; COMPUTERIZED TOMOGRAPHY; FILM DOSIMETRY; IONIZATION CHAMBERS; LINEAR ACCELERATORS; MONTE CARLO METHOD; PHASE SPACE; QUALITY ASSURANCE; RADIATION DOSE DISTRIBUTIONS; RADIOTHERAPY; VERIFICATION

Citation Formats

Barbeiro, A.R., Ureba, A., Baeza, J.A., Jimenez-Ortega, E., Plaza, A. Leal, Linares, R., Mateos, J.C., and Velazquez, S.. SU-E-T-644: QuAArC: A 3D VMAT QA System Based On Radiochromic Film and Monte Carlo Simulation of Log Files. United States: N. p., 2015. Web. doi:10.1118/1.4925007.
Barbeiro, A.R., Ureba, A., Baeza, J.A., Jimenez-Ortega, E., Plaza, A. Leal, Linares, R., Mateos, J.C., & Velazquez, S.. SU-E-T-644: QuAArC: A 3D VMAT QA System Based On Radiochromic Film and Monte Carlo Simulation of Log Files. United States. doi:10.1118/1.4925007.
Barbeiro, A.R., Ureba, A., Baeza, J.A., Jimenez-Ortega, E., Plaza, A. Leal, Linares, R., Mateos, J.C., and Velazquez, S.. Mon . "SU-E-T-644: QuAArC: A 3D VMAT QA System Based On Radiochromic Film and Monte Carlo Simulation of Log Files". United States. doi:10.1118/1.4925007.
@article{osti_22538153,
title = {SU-E-T-644: QuAArC: A 3D VMAT QA System Based On Radiochromic Film and Monte Carlo Simulation of Log Files},
author = {Barbeiro, A.R. and Ureba, A. and Baeza, J.A. and Jimenez-Ortega, E. and Plaza, A. Leal and Linares, R. and Mateos, J.C. and Velazquez, S.},
abstractNote = {Purpose: VMAT involves two main sources of uncertainty: one related to the dose calculation accuracy, and the other linked to the continuous delivery of a discrete calculation. The purpose of this work is to present QuAArC, an alternative VMAT QA system to control and potentially reduce these uncertainties. Methods: An automated MC simulation of log files, recorded during VMAT treatment plans delivery, was implemented in order to simulate the actual treatment parameters. The linac head models and the phase-space data of each Control Point (CP) were simulated using the EGSnrc/BEAMnrc MC code, and the corresponding dose calculation was carried out by means of BEAMDOSE, a DOSXYZnrc code modification. A cylindrical phantom was specifically designed to host films rolled up at different radial distances from the isocenter, for a 3D and continuous dosimetric verification. It also allows axial and/or coronal films and point measurements with several types of ion chambers at different locations. Specific software was developed in MATLAB in order to process and evaluate the dosimetric measurements, which incorporates the analysis of dose distributions, profiles, dose difference maps, and 2D/3D gamma index. It is also possible to obtain the experimental DVH reconstructed on the patient CT, by an optimization method to find the individual contribution corresponding to each CP on the film, taking into account the total measured dose, and the corresponding CP dose calculated by MC. Results: The QuAArC system showed high reproducibility of measurements, and consistency with the results obtained with the commercial system implemented in the verification of the evaluated treatment plans. Conclusion: A VMAT QA system based on MC simulation and high resolution dosimetry with film has been developed for treatment verification. It shows to be useful for the study of the real VMAT capabilities, and also for linac commissioning and evaluation of other verification devices.},
doi = {10.1118/1.4925007},
journal = {Medical Physics},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}