Gonads Exposure to Scattered Radiationand Associated Second Cancer Risk From Pelvic Radiotherapy

 The purpose of this study was to evaluate the risk of gonad cancer induction attributable to pelvic radiation therapy in adult patients. 

 By characterizing the peripheral dose the TLDs were placed on the testis and ovary in two fractions of radiotherapy. All patients delivered a 45 Gy total dose in 4 fields in the prone position with 3D planning. The doses from a linear accelerator at 18 MV photon beam, were investigated.

 The mean excess relative risk (ERR) based on the BEIR IIV models of men and women after 5 and 10 year of radiotherapy treatment for pelvic radiotherapy was 0.825±0.168, 0.948±0.504, 0.700±0.135, and 0.803±0.407 respectively.

 Estimating the second cancer risk of untargeted organs is crucial in radiotherapy. Using the single-energy mode linear accelerator and proper shields can be minimized the out-of-field doses.