Comparability of three output prediction models for a compact passively double-scattered proton therapy system.

Comparability of three output prediction models for a compact passively double-scattered proton therapy system. J Appl Clin Med Phys. 2017 Apr 19;: Authors: Ferguson S, Chen Y, Ferreira C, Islam M, Keeling VP, Lau A, Ahmad S, Jin H Abstract The purpose of this study was to investigate comparability of three output prediction models for a compact double-scattered proton therapy system. Two published output prediction models are commissioned for our Mevion S250 proton therapy system. Model A is a correction-based model (Sahoo et al., Med Phys, 2008;35(11):5088-5097) and model B is an analytical model which employs a function of r = (R'-M')/M' (Kooy et al., Phys Med Biol, 2005;50:5487-5456) where R' is defined as depth of distal 100% dose with straggling and M' is the width between distal 100% dose and proximal 100% dose with straggling instead of the theoretical definition due to more accurate output prediction. The r is converted to ((R-0.31)-0.81 × M)/(0.81 × M) with the vendor definition of R (distal 90% dose) and M (distal 90% dose-to-proximal 95% dose), where R' = R-0.31 (g cm(-2) ) and M' = 0.81 × M (g cm(-2) ). In addition, a quartic polynomial fit model (model C) mathematically converted from model B is studied. The outputs of 272 sets of R and M covering the 24 double scattering options are measured. Each model's predicted output is compared to the measured output. For the total dataset, the percent differ...
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research