Evaluation of dose distributions in PTV and organs at risk in left-sided breast cancer, treated by tangential wedged technique in Tohid radiotherapy center in Sanandaj

Abstract

Background and Aim: The goal of radiotherapy is delivering enough dose to the tumor and the lowest dose to the organ at risks (OAR). The aim of this study was to evaluate the received dose and homogenous dose in the target volume. Also we evaluated the dose received by the heart and lung during the treatment of breast cancer by using tangential wedge beam technique. Material and Method: Twenty patients with left sided breast cancer and conserved breast were divided into two groups: patients with large breasts and patients with small breasts. Treatment design was performed by Iso -gary software The Dose Volume Histograms (DVHs) was used to measure the doses received by the target volume, heart and lungs. Result: Dose homogeneity index (DHI) was equal for both groups. Homogeneity index (HI) of small breasts was lower significantly (p=0.001) and the dose distribution was better. The percentage of heart and lung involvement in the patients with big breasts at all dose levels was more but the difference wasn’t significant. Conclusion: HI for target volume and dose received by organs at risks were higher in the patients with big breasts. Therefore treatment planning for the patients with bigger breasts needs more attention. Also calculation of evaluation indexes is more essential for these patients. Doses received by the heart and lung were compatible with standard levels and also the radiation risk for the heart and lung was within the acceptable level.