Out of Field Breast Doses as an Undesired Consequence of Cervical Cancer Radiotherapy

Abstract

OBJECTIVEUnwanted doses may occur in distant organs, outside of the region where we want to be irradiated in patients treated with radiotherapy. These doses cannot be accounted accurately by the treatment planningsystem (TPS) yet. In our study, the doses received by the breast tissue outside the field of irradiation areaimed to investigate dosimetrically in irradiation with three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT) and volumetric arc therapy (VMAT) techniquesfor cervical cancer.METHODSThe patient was simulated in Alderson Rando phantom and irradiated with three different techniquesin Varian DHX (Rapidarc) linear accelerator with 48 Gy in 24 fractions. Doses that occur in the breasttissue were measured using thermoluminescent dosimeters and compared with each other and the dataobtained from TPS.RESULTSThe dose values in the right and left breasts were found to be statistically similar to each other (p>0.05),whereas significant differences were detected between different techniques. The mean calculated breastdoses were 7.16±1.61 cGy in 3D-CRT, 27,75±3,88 cGy in IMRT and 12,20±2,65 cGy in VMAT, respectively.CONCLUSIONThe breast tissue doses are significantly lower in 3D-CRT and VMAT compared with IMRT. This findingshould be considered while choosing a treatment technique, especially in young patients with cervicalcancer.