ESTRO 2023 - Abstract Book

S2073

Digital Posters

ESTRO 2023

PO-2306 Daily Bolus Position Variability with Dosimetric Implications in Adjuvant Breast Cancer Radiotherapy

G.A.M. Salagean 1,2 , K. Varga 1 , L. Kun-Balint 1 , D. Cojocaru 1 , R. Neag 1 , M. Cojocaru-Laboncz 1 , A. Cudlici 1 , C. Duran 1 , Z. Balint 2 , D. Portik 1 1 TopMed Medical Centre, Radiotherapy, Targu-Mures, Romania; 2 Babes Bolyai University, Faculty of Physics, Cluj-Napoca, Romania Purpose or Objective Bolus material is a tissue equivalent material commonly used on the skin surface of the patient to maximize or add radiation dose to an irradiated area during radiotherapy (RT). In this study we analyzed the position variability of the bolus material and the dosimetric changes it determines in target volume (TV) coverage and the organ at risk (OAR) Materials and Methods We retrospectively evaluated 8 cases of breast cancer irradiation in which bolus materials were used to obtain better skin surface coverage. Adjuvant RT was administered at a dose of 50Gy in 25 fractions, to the chest wall ± nodal regions. For each patient, the daily positioning variability was noted, and the movement of the bolus was categorized as being either a ‘positive’ shift (PosS) or a ‘negative’ shift (NegS) (Figure 1).