Evaluation of bolus material effect on chest wall by using field in field IMRT and 3 dimensional conformal treatment planning techniques

The purpose of this study is to investigate the effect of bolus effect on target volume and organ at risks by modifying the number of bolus used in patients who will undergo radiation therapy after mastectomy and creating treatment plans with 3BKRT and FIF IMRT treatment techniques. Twenty female breast cancer patients who had mastectomy operation in our study were treated with 6 MV energetic photon, with all of the bolus, without any bolus, and 11 fractional boluses, and total 25 fractions from 2 Gy were treated using 3DCRT and FIF IMRT techniques. CTV, heart, lung and counter lung dose and volume values were statistically analyzed with SPSS 18.0 program with 7 different plans. As a result of the analyzes made, the FIF IMRT dose values for the target volume were found to be advantageous compared to 3DCRT and the relation between them was found statistically significant (p <0.05). However, when the use of bolus material was increased, the mean dose values were increased. In neighboring organs such as the heart and lung, the mean dose of 3DCRT technique was found to be lower and it was observed that the average was increased due to bolus use. The opposite lung dose did not change much for both techniques. Target volume dose homogeneity resulting from volumetric changes from anatomic structures and surgical operations that vary from person to person and differences in organ doses at risk can be observed. The ideal treatment is to decide on the right treatment to patients specifically. Key words: Mastectomy, Bolus, 3DCRT, FIF IMRT