Accuracy of Beamscan Software in Determining Inflection Point from FFF Beam Profile using Several Array Detectors

Abstract The goal of this study is to determine the accuracy of the PTW Beamscan program in determining the inflection point from an FFF Beam Profile utilizing Multiple Detectors. Profile measurements were taken with PTW’s 729, 1500, and 1600 and the Starcheck system, the Pinpoint 3D with Beamscan system, and Linac’s EPID. Using the first-order derivative employed in the Excel spreadsheet and Beamscan software, raw measured data were used to determine the inflection point, and the FWHM was calculated. The accuracy of inflection points and FWHM between the Excel sheet calculation and the software program were investigated. For 10X10 cm2 in the 729 Array, the greatest differences in FWHM were 5.16 mm and 5.04 mm for the X6 FFF and X10 FFF Energies, respectively. The largest difference was 2.26 mm for 1600 SRS arrays with a 15×15 cm2 field size. The difference in FWHM between Manual and software analysis for 10X10 cm2 and 20X20 cm2 Field Sizes is in decreasing order for detectors from 729, 1500, 1600 SRS, Starcheck, Pinpoint 3D, and EPID. In contrast, there is no climbing or declining pattern detected in the difference in Field Width for the 15×15 cm2 Field Size. Similarly, for all detectors except the 1600 SRS array, the peak of the first-order derivative occurs at the chamber position for a 15X15 cm2 field size. EPID outperformed all other detectors in terms of agreement with values obtained by software analysis. The data show that increased resolution improves inflection point detection. Thus, it is shown that BeamScan software is ideal for FFF beam profile analysis utilizing inflection point analysis.