ESTRO 2024 - Abstract Book

S3171

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Only for criterion 3%3 mm the average %GP was acceptable for all VMAT plans, with average rates of 97.18%. For criterion 2%/2 mm %GP was 86.76%. The %DE between 0.1 and 6.6 were observed (%DEmean =1.59%). The average AUC value of ROC was 0.555 ± 0.11 and 0.471 ± 0.11 for 3%3 mm, 2%/2mm respectively. 3%/3 mm criteria had a better prediction on the %DE than did 2%/2 mm, but the accuracy of both gamma index methods were not good enough for clinical acceptable with AUC values lower than 0.6

Conclusion:

Value of AUC confirmed the low diagnostic usefulness of the %GP parameter for examined SBRT plans. Low sensitivity of 3%/3 mm gamma method was confirmed. More efficient methods for evaluation dosimetric errors should be urgent implemented.

Keywords: SBRT, gamma index, (ROC) Curve analysis

63

Digital Poster

Assessment of various dosimetric correction factors for small and large field sizes of photon beams

Boopathi M 1,2 , Khanna D 1 , Mohandass P 3 , Venkatraman P 4 , Gogul Priean V 5

1 Karunya Institute, Department of Applied Physics, Karunya Institute of Technology and Sciences, Coimbatore, India. 2 Dharan Cancer Speciality Centre Pvt Ltd, Radiation Oncology, Salem, India. 3 Fortis Cancer Institute, Radiation