Multi-Institutional Analysis of Source Model Parameters for Beam Commissioning of Scanning Proton Therapy Treatment Planning System

Document Type

Conference Proceeding

Publication Date

6-2024

Publication Title

International Journal of Particle Therapy

Abstract

Background and aims: Standardizing beam modeling in the treatment planning system (TPS) is challenging due to machinespecific configuration variations. The primary goal of this study is to create a beamline-specific repository of source model parameters and beam commissioning data for scanning proton therapy (PT) TPSs. Additionally, it aims to create a cross-reference database for common PT vendors and beamline models. Methods: We conducted a survey of 28 PT centers to gather beam commissioning source model parameters used in their TPS, ensuring a diverse selection of beamlines from different vendors: Hitachi, IBA, Varian, and Mevion. For each PT center, we collected (i) beam meterset calibration in protons per MU, (ii) in-air spot size at isocenter in terms of standard deviation in x- (crossline, σx) and y- (inline, σy) directions, (iii) in-air angular spread at isocenter in xdirection (θx) and y-direction (θy). We plotted each parameter as a function of nominal energy on the same graph, grouping them by a similar beamline. We calculated the variations for each parameter group. For each beamline, we performed an analysis of variance test for each parameter to determine whether it is statistically different across different centers. We reported the ratio of the variation between sample means to the variation within samples (F-value) and the corresponding p-value for each test. Results: Figures 1 and 2 show the summary of beam commissioning source model parameters and percent difference of each parameter from the mean, respectively. The lowest and highest variation and statistics between the same beamlines was observed for IBA’s ProteusOne and IBA’s ProteusPlus Universal Nozzle, respectively. Conclusions: Because of the PT beamline complexity and continuous development, there is no vendor’s representative (“golden”) beam data like in LINACs at this stage. This work will help crosscheck beam model uncertainty to minimize human factors during TPS commissioning. Furthermore, this data proves valuable in Monte Carlo applications and research, as it aids in establishing phase space parameters to avoid the necessity of modeling the entire beamline. Finally, the results of this study will have an indispensable educational value by providing valuable insight.

Volume

12

Issue

Suppl

First Page

148

Comments

62nd Annual Conference of the Particle Therapy Cooperative Group (PTCOG), June 10-15, 2024, Singapore

DOI

10.1016/j.ijpt.2024.100436

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