ESTRO 2024 - Abstract Book

S3571

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

The mean CHI values for PTVT and PTV (T-B) were 2.498, 26.81 respectively. The HIs mean values for PTVT and PTV (T-B) respectively were D5/D95: 1.22,1.14, Dmax/Dmin - 1.59,1.37, (D1–D98)/Dp - 0.26,0.19, D5–D95/Dp - 0.22,0.14, Dmax/Dp - 1.30,1.2, (D2 − D98)/D50 - 0.21,0.17, (D2 − D98)/Dp - 0.25,0.18. Statistical analysis using Pearson chi square test demonstrated significant associations with p<0.05. CHI specifically developed to describe the dose heterogeneity within the PTV further showcases its unique capability to assess the heterogeneity inside PTV excluding the boost volume. The VMAT has the ability to deliver different doses to different volumes at the same time. Our results show that CHI seems to have wide range of values and has the potential to foresee the results for high dose volume boost inside the target. Higher CHI, better dose distribution inside the target region which is outside the boost volume.

Table 1: Table illustrates the various homogeneity indices evaluated three PTV’s named as PTVT (target volume including boost volume), PTVB (boost or high-risk volume), PTV (T-B) target volume excluding boost volume

Figure 1: Figure 1a depicts the dose distribution for SIB-VMAT planning technique in Monaco TPS. The yellow region represents the dose distribution in PTVB volume region i.e. Boost Volume. The blue region represents the dose distribution in the PTVT region i.e. Target region including boost volume. Figure 1b represents the enlarged coronal view of the dose distribution for SIB-VMAT plan.