HYBRID IMRT RADIATION TECHNIQUE COMPARISON WITH 3D-CRT FOR LEFT-SIDED WHOLE BREAST CANCER

Abstract

To identify the best treatment technique for patients with left-sided breast cancer, we compared plans obtained with a hybrid intensity-modulated radiation therapy (hIMRT) and conventional threedimensional conformal radiation therapy (3D-CRT). Dosimetric indices for PTVs and OARs were calculated. Also, the dose coverage, homogeneity index, conformity index of the target, and the dose volumes of critical structures were analyzed. A sample of seven patients who were selected randomly treated in University Clinical Center Kragujevac between 2019 and 2020 was selected for the study. Therapy plans for both techniques were made with an ECLIPSE treatment planning system for each patient based on the same images and contours. The hybrid IMRT technique consists of two static opposed tangential fields and four optimized IMRT fields (dose ratio 70:30). For 3D-CRT planning, one isocenter with half-beam blocked tangential fields with wedges was used. All treatment plans were generated with 6 MV photon beam. Hybrid IMRT plans compared to the 3D-CRT resulted in better dose delivered to 95% (D95) of the planning target volume (PTV) and better heterogeneity HI and conformity CI. Protection for critical organs such as the heart, lungs, and contralateral breast is slightly worse than those obtained by 3D-CRT.