ESTRO 2024 - Abstract Book

S4655

Physics - Optimisation, algorithms and applications for ion beam treatment planning

ESTR0 2024

Figure 1 . Example of dose painting and sequential boost plans of a skull-based chordoma patient, with relative dose prescriptions and quality factor maps. DP: dose painting; SB: sequential boost.

Results:

DP with 4 beams decreases D mean and D max and increases D min and D 98% , while DP with 2 beams decreases D mean , D max and D min , and increases D 98% in radiotherapy targets compared to SB plans ( Table 1 ). DP with 4 beams increases D mean , D min and D 98% and decreases D max , while DP with 2 beams decreases D mean , D min , D max and D max in targeted recurrence volume compared to SB plans ( Table 1 ). DP with 4 and 2 beams increases conformity in the GTV to a mean QF of (97.8±0.5)% and (94.4±2.1)% (p<0.001 and p=0.29, respectively), CTV LR to a mean QF of (95.0±1.2)% and (91.8±1.5)% (p<0.001 and p=0.002, respectively) and PTV LR to a mean QF of (94.0±1.6)% and (92.0±1.4)% (p<0.001 and p=0.002, respectively) compared to SB plans, which have a mean QF of (93.0±1.9)%, (82.2±3.8)% and (81.0±4.5)%, in the GTV, CTV LR and PTV LR , respectively. DP with 4 beams increases TCP in GTV (p=0.06) to a mean of (99.2±1.1)%, while DP with 2 beams decreases TCP in GTV (p=0.33) to a mean of (71.8±41.4)% compared to SB plans, which have a mean of (91.2±7.9)%. DP at 4 beams meets clinical goals and increases the percentage volume of GTV receiving the target dose of 74 Gy (RBE) to (87.4±4.7)% compared to SB plans (72.4±13.9)%.