Document Type

Conference Proceeding

Publication Date

10-2024

Publication Title

Medical Physics

Abstract

Purpose: To create a beamline-specific repository of source model parameters and beam commissioning data for scanning proton therapy (PT) treatment planning system (TPS).

Methods: We surveyed 28 PT centers, collecting beam commissioning source model parameters of diverse beamlines from different vendors: Hitachi, IBA, Varian, Mevion. Parameters included (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 x-direction (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 and reported corresponding F-values and p-values to assess statistical differences across centers for each parameter within each beamline.

Results: Figures 1 and 2 present an overview of beam commissioning source model parameters and the percentage difference of each parameter from the mean, respectively. The IBA’s ProteusOne exhibited the lowest variation, while the IBA’s ProteusPlus Universal Nozzle demonstrated the highest variation and associated statistics among the same beamlines.

Conclusion: Due to the intricate and ever-evolving nature of PT beamlines, there is no vendor’s representative (“golden”) beam data like in LINACs at this stage. This study is pivotal in mitigating human factors during TPS commissioning by cross-verifying beam model uncertainty. Moreover, the data serves as a crucial asset in Monte Carlo applications and research, aiding in defining of phase space parameters, thereby eliminating the need to model the entire beamline. Lastly, the findings of this investigation hold significant educational value, offering profound insights into the distinctive characteristics and capabilities of diverse beamlines.

Volume

51

Issue

10

First Page

7693

Comments

American Association of Physicists in Medicine 66th Annual Meeting & Exhibition, July 21-25 2025, Los Angeles, CA

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