ESTRO 2024 - Abstract Book

S961

Clinical - CNS

ESTRO 2024

boost PTV. 16 patients received Dmax of >54Gy for brainstem, however D1-10cc received by brainstem was <59Gy in all patients. Optic chiasma constraints were not achieved in 3 patients which were pineal tumors having close proximity between target and chiasma. Dmean, Integral dose, V80%, V50%, V20%, V10%, and V5% to OARs were comparable with standard published data. Hematological toxicities included: leukopenia Gr 1 – 4 (18.75%, 50%, 18.75%, 12.5%), anemia Gr 0 – 4 (25%, 37.5%, 25%, 12.5%, 0%) and thrombocytopenia Gr 0 – 4 (25%, 37.5%, 31.25%, 6.25%, 0%) were reported. Skin toxicities: Gr 1-4 (56.25%, 37.5%, 6.25%, 0%). No grade 4 toxicities were observed except leukopenia. 2.5 cm width had higher fractional MU and beam-on time (15553.43 and 894.32 sec) compared to 5 cm width (9158.66 and 525.86 sec) leading to incidence of >grade 2 toxicities - 73.33% in 2.5 cm & 42.42% in 5 cm plans. 9 patients out of 24 required a break in the course of radiation due to acute toxicities.

Conclusion:

Helical tomotherapy achieves good target coverage, dose homogeneity and conformality, sparing of OARs with obviating field junctions and discontinuous couch and gantry movements. Acute toxicities were acceptable. However, a relatively larger number of monitor units associated with helical tomotherapy could result theoretically in a higher risk of secondary malignancies.

Keywords: Craniospinal Irradiation,Tomotherapy,Helical IMRT

References:

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