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Title: SU-F-T-216: Evaluating Dosimetry Accuracy of a Treatment Planning System On Small Proton Fields

Abstract

Purpose: This study is aiming to identify the smallest field size for which a treatment planning system (TPS) can accurately calculate the relative dose distribution. The finding would be used as a guideline to choose the smallest proton field for clinical treatment. Methods: Mevion S250™ double scattering proton delivery system and Eclipse™ TPS (Varian) with pencil beam convolution (PBC) dose algorithm were used in this study. Square sized fields of 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, and 10 cm were planned on a cubical water phantom with iso-center placed at 10 cm depth. All beams used the same proton beam option: range 15 cm and modulation 10 cm. Dose in water was calculated without any compensator. Gafchromic™ EBT3 film and diode detectors were used to measure the central axis dose distribution and lateral dose profiles at 5 cm, 10 cm, and 14 cm depth. Results: The preliminary film measurement shows good agreement between Eclipse calculated lateral dose profiles for all tested field sizes. The differences on full width half maximum were ≤ 1 mm while the differences on the penumbras were between 1 mm and 2 mm between Eclipse and film. For the depth dose, Eclipsemore » results matched well with film measurements for field sizes down to 2 cm{sup 2}. With smaller field size of 1 cm{sup 2}, Eclipse was able to predict the decreasing of SOBP due to the lack of lateral charged particle equilibrium in depth. However, it did not match the film measurement. Diode measurement results will be available at the time of presentation. Conclusion: The PBC dose algorithm in Eclipse can accurately calculate relative dose distribution in double scattered proton system for field size down to 2 cm{sup 2}.« less

Authors:
; ; ; ;  [1]
  1. Rutgers University, New Brunswick, NJ (United States)
Publication Date:
OSTI Identifier:
22648833
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; CHARGED PARTICLES; DEPTH DOSE DISTRIBUTIONS; DOSIMETRY; PLANNING; PROTON BEAMS; RADIOTHERAPY

Citation Formats

Zhang, M, Xiao, Z, Zou, J, Chen, T, and Yue, N. SU-F-T-216: Evaluating Dosimetry Accuracy of a Treatment Planning System On Small Proton Fields. United States: N. p., 2016. Web. doi:10.1118/1.4956355.
Zhang, M, Xiao, Z, Zou, J, Chen, T, & Yue, N. SU-F-T-216: Evaluating Dosimetry Accuracy of a Treatment Planning System On Small Proton Fields. United States. doi:10.1118/1.4956355.
Zhang, M, Xiao, Z, Zou, J, Chen, T, and Yue, N. Wed . "SU-F-T-216: Evaluating Dosimetry Accuracy of a Treatment Planning System On Small Proton Fields". United States. doi:10.1118/1.4956355.
@article{osti_22648833,
title = {SU-F-T-216: Evaluating Dosimetry Accuracy of a Treatment Planning System On Small Proton Fields},
author = {Zhang, M and Xiao, Z and Zou, J and Chen, T and Yue, N},
abstractNote = {Purpose: This study is aiming to identify the smallest field size for which a treatment planning system (TPS) can accurately calculate the relative dose distribution. The finding would be used as a guideline to choose the smallest proton field for clinical treatment. Methods: Mevion S250™ double scattering proton delivery system and Eclipse™ TPS (Varian) with pencil beam convolution (PBC) dose algorithm were used in this study. Square sized fields of 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, and 10 cm were planned on a cubical water phantom with iso-center placed at 10 cm depth. All beams used the same proton beam option: range 15 cm and modulation 10 cm. Dose in water was calculated without any compensator. Gafchromic™ EBT3 film and diode detectors were used to measure the central axis dose distribution and lateral dose profiles at 5 cm, 10 cm, and 14 cm depth. Results: The preliminary film measurement shows good agreement between Eclipse calculated lateral dose profiles for all tested field sizes. The differences on full width half maximum were ≤ 1 mm while the differences on the penumbras were between 1 mm and 2 mm between Eclipse and film. For the depth dose, Eclipse results matched well with film measurements for field sizes down to 2 cm{sup 2}. With smaller field size of 1 cm{sup 2}, Eclipse was able to predict the decreasing of SOBP due to the lack of lateral charged particle equilibrium in depth. However, it did not match the film measurement. Diode measurement results will be available at the time of presentation. Conclusion: The PBC dose algorithm in Eclipse can accurately calculate relative dose distribution in double scattered proton system for field size down to 2 cm{sup 2}.},
doi = {10.1118/1.4956355},
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}
}