The Effectiveness of Surface Lead Shielding of Gonads Outside the Primary X-ray Beam

Abstract

Objective: To determine the effectiveness of surface radiation shields of gonads outside the primary x-ray beam. Methods: Radiographic and computed tomography air kerma measurements were made on a standard anthropomorphic phantom to quantify the amount of external and internal scatter radiation to the gonads of males and females. These amounts were calculated from air kerma measurements using three different methods: with no shielding, with surface lead shields, and with axial lead shields located between the gonads and the primary x-ray beam. Measurements were made with the distance of the primary radiation field to the dosimeter ranging from 0 to 20 cm and at kVp values ranging from 60 to 120. Results: The contribution of external radiation to the total amount of gonadal radiation during radiographic procedures was 15 ± 13.1% for males and 5 ± 5.6% for females, respectively. For computed tomography, external radiation contributed 9 ± 6.8% and 4.3 ± 8.1% to the total gonadal radiation for males and females, respectively. Conclusion: For body parts outside the primary radiation beam, the main source of radiation is from internal scatter. Because surface radiation shields can only protect against external radiation, their value as radiation protection devices is limited.