ESTRO 2023 - Abstract Book

S1835

Digital Posters

ESTRO 2023

5.51.10 treatment planning system. The relationship between BMI and setup errors was assessed using the Pearson correlation coefficient. Results Correlations between BMI and errors show a statistical relevance on posterior direction for 0° inclination (table 1) and for tangent parameters the correlation was observed at CLD for 7.5° and CCD for both inclinations. Regarding target volume dosimetry under systematic and random errors, the study showed that systematic errors are more pronounced than random errors (table 2). For group C positioned on 7.5° board, the mean target coverage for 3DCRT (46.85Gy), IMRT (47.25Gy) and VMAT (47.37Gy) under systematic errors did not reach 95% of the prescribed dose. The organs at risk (OARs) were better protected with modulated techniques, with the percentage of OARs exceeding the recommended dose limits being smaller

for modulated plans than for conformal treatment (table 2). Table 1. Statistical correlation between BMI and setup errors

Table 2. Target and OARs

Conclusion Evaluating the factors that impact on target coverage and dose constrains for organs at risk can improve the outcome of radiotherapy. Furthermore, providing correlations between variables such as BMI and positioning errors, an optimal decision on the choice of board immobilization and inclination can be made, leading to a more personalized treatment.

PO-2060 Analysis of different dosimetric indices using various formulae in cranial srs /srt planning

V. Sundaram 1 , T. Vasudeva 1 , A.K. Mani 1 , P. Mohandass 2 , D. Khanna 3 , S. Palanivel 4 , P. Muthuvel 1 , A. Prakash 5

1 Meherbai Tata Memorial Hospital, Department of Radiation Oncology, Jamshedpur, India; 2 Fortis Hospital, Department of Radiation Oncology, Punjab, India; 3 Karunya Institute of technology and sciences, Department of Applied Physics,