ESTRO 2025 - Abstract Book

S3696

Physics - Quality assurance and auditing

ESTRO 2025

at Half Maximum (FWHM) below 2mm and dose differences within ± 2% . High 3D GPRs were observed for TPS vs. myQA iON comparison ( 99.3±0.9% ). In the heterogeneous phantom analysis, differences in distal R 90 between computed and measured ranges were still within 1mm for TPS but exceeded this value for myQA iON (see Table 1 for detailed results). Lower GPRs were observed in this setting ( 97.0±1.4% ) compared to the homogenous phantom ( 99.5±0.1% ). Clinical beam analysis showed good agreement, with slightly lower 3D GPRs for breast treatment plans, likely due to the beam encountering a tissue-lung interface. myQA iON computations without log-files yielded an average 3D GPR of 97.4±1.6% for breast beams, compared to 98.9±0.8% for other treatment sites. Log-files computations resulted in a 3D GPR average reduction of 0.3±0.4% , as can be observed in Figure 1 , which summarized the 3D GPR distributions.