Evaluation of the surface dose for total body irradiation (TBI) technique with parallel-opposed anterior posterior geometry

Abstract

Aim: Total body irradiation (TBI) is an external radiotherapy technique in which the whole body including the superficial regions is required to receive the therapeutic dose. The purpose of this study is to evaluate the received surface dose during TBI technique. Methods and materials: The anterior/posterior (AP/PA) TBI was implemented with 18-MV photon beam at 312-cm treatment distance for human-like phantom. The GAFCHROMIC-EBT3 films were used for superficial dose measurements. Results and discussion: The percentage of surface-absorbed dose relative to the prescription point for 8 points of measurements was between 102·78–121·48% and 104·51–127·43% at 5 and 10 mm depth, respectively. In the chest wall region due to the presence of lung blocks, the absorbed dose was below the acceptable level, so an electron boost was required to increase the chest wall absorbed dose. Conclusions: According to the results, the implemented technique was able to deliver sufficient dose to the shallow surface of phantom’s body.