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

Abstract

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

Methods: 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.

Results: 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.

Conclusion: 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.