Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer

Objective: Dose-averaged linear energy transfer (LETD) is one of the factors which determines relative biological effectiveness (RBE) for treatment planning in proton therapy. It is usually determined from Monte Carlo (MC) simulation. However, no standard simulation protocols were established for sa...

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Main Authors: Koh, Calvin Wei Yang, Tan, Hong Qi, Ang, Khong Wei, Park, Sung Yong, Lew, Wen Siang, Lee, James Cheow Lei
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2020
Subjects:
RBE
Online Access:https://hdl.handle.net/10356/144097
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1440972023-02-28T19:51:06Z Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer Koh, Calvin Wei Yang Tan, Hong Qi Ang, Khong Wei Park, Sung Yong Lew, Wen Siang Lee, James Cheow Lei School of Physical and Mathematical Sciences National Cancer Centre Singapore Science Proton Therapy RBE Objective: Dose-averaged linear energy transfer (LETD) is one of the factors which determines relative biological effectiveness (RBE) for treatment planning in proton therapy. It is usually determined from Monte Carlo (MC) simulation. However, no standard simulation protocols were established for sampling of LETD. Simulation parameters like maximum step length and range cut will affect secondary electrons production and have an impact on the accuracy of dose distribution and LETD. We aim to show how different combinations of step length and range cut in GEANT4 will affect the result in sampling of LETD using different MC scoring methods. Methods: In this work, different step length and range cut value in a clinically relevant voxel geometry were used for comparison. Different LETD scoring methods were established and the concept of covariance between energy deposition per step and step length is used to explain the differences between them. Results: We recommend a maximum step length of 0.05 mm and a range cut of 0.01 mm in MC simulation as this yields the most consistent LETD value across different scoring methods. Different LETD scoring methods are also compared and variation up to 200% can be observed at the plateau of 80 MeV proton beam. Scoring Method one has one of the lowest percentage differences compared across all simulation parameters. Conclusion: We have determined a set of maximum step length and range cut parameters to be used for LETD scoring in a 1 mm voxelized geometry. LETD scoring method should also be clearly defined and standardized to facilitate cross-institutional studies. Advances in knowledge: Establishing a standard simulation protocol for sampling LETD would reduce the discrepancy when comparing data across different centres, and this can improve the calculation for RBE. Accepted version 2020-10-13T05:19:33Z 2020-10-13T05:19:33Z 2020 Journal Article Koh, C. W. Y., Tan, H. Q., Ang, K. W., Park, S. Y., Lew, W. S., & Lee, J. C. L. (2020). Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer. British Journal of Radiology, 93(1112), 1-11. doi:10.1259/bjr.20200122 0007-1285 https://hdl.handle.net/10356/144097 10.1259/bjr.20200122 1112 93 1 11 en British Journal of Radiology © 2020 The Authors (Published by the British Institute of Radiology). All rights reserved. This paper was published in British Journal of Radiology and is made available with permission of The Authors (Published by the British Institute of Radiology). application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science
Proton Therapy
RBE
spellingShingle Science
Proton Therapy
RBE
Koh, Calvin Wei Yang
Tan, Hong Qi
Ang, Khong Wei
Park, Sung Yong
Lew, Wen Siang
Lee, James Cheow Lei
Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer
description Objective: Dose-averaged linear energy transfer (LETD) is one of the factors which determines relative biological effectiveness (RBE) for treatment planning in proton therapy. It is usually determined from Monte Carlo (MC) simulation. However, no standard simulation protocols were established for sampling of LETD. Simulation parameters like maximum step length and range cut will affect secondary electrons production and have an impact on the accuracy of dose distribution and LETD. We aim to show how different combinations of step length and range cut in GEANT4 will affect the result in sampling of LETD using different MC scoring methods. Methods: In this work, different step length and range cut value in a clinically relevant voxel geometry were used for comparison. Different LETD scoring methods were established and the concept of covariance between energy deposition per step and step length is used to explain the differences between them. Results: We recommend a maximum step length of 0.05 mm and a range cut of 0.01 mm in MC simulation as this yields the most consistent LETD value across different scoring methods. Different LETD scoring methods are also compared and variation up to 200% can be observed at the plateau of 80 MeV proton beam. Scoring Method one has one of the lowest percentage differences compared across all simulation parameters. Conclusion: We have determined a set of maximum step length and range cut parameters to be used for LETD scoring in a 1 mm voxelized geometry. LETD scoring method should also be clearly defined and standardized to facilitate cross-institutional studies. Advances in knowledge: Establishing a standard simulation protocol for sampling LETD would reduce the discrepancy when comparing data across different centres, and this can improve the calculation for RBE.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Koh, Calvin Wei Yang
Tan, Hong Qi
Ang, Khong Wei
Park, Sung Yong
Lew, Wen Siang
Lee, James Cheow Lei
format Article
author Koh, Calvin Wei Yang
Tan, Hong Qi
Ang, Khong Wei
Park, Sung Yong
Lew, Wen Siang
Lee, James Cheow Lei
author_sort Koh, Calvin Wei Yang
title Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer
title_short Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer
title_full Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer
title_fullStr Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer
title_full_unstemmed Standardizing Monte Carlo simulation parameters for a reproducible dose-averaged linear energy transfer
title_sort standardizing monte carlo simulation parameters for a reproducible dose-averaged linear energy transfer
publishDate 2020
url https://hdl.handle.net/10356/144097
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