(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose:
The use of gonadal shielding in radiography is a topic of debate, and this study provides accurate dose reduction estimates for ideal and non-ideal shield placement for adult and pediatric patients.
Methods:
An adult, 5-year, and newborn CIRS anthropomorphic phantom was voxelized to perform Monte Carlo simulations of primary and scatter photon transport during abdomen radiographic exams. Circular lead shields with lead thickness equivalent of 0.5 mm, and radii of 4.2 cm, 3.6 cm and 2.5 cm were used for the adult, 5-year, and newborn phantoms, respectively. Dose at the ovaries and testes with and without the lead gonadal shields were calculated. The reduction in gonadal dose from shielding, when the shields were not ideally placed directly over the gonads were evaluated; gonadal shielding was translated up to 8 cm from ideal placement. MOSFET detectors were used to experimentally validate the simulation results.
Results:
MOSFET dose measurements agreed to better than 1.1% and 9% for unshielded testes and ovaries, respectively. Gonadal shields when placed ideally over the ovaries reduced dose by 58%, 63% and 72 % for adult, 5-year, and new-born phantoms, respectively. Similarly for the testes, dose reduction of 84% for the adults and 90% for the 5-year old and newborn phantom were calculated. When the shields are displaced by 4 cm from the ideal location, the reduction in dose was 31% and 33% for the adult ovaries and testes, respectively. A 4 cm shield displacement from the ideal location for 5-year and newborn resulted in dose reduction of 6% for the ovaries, and 5% for the testes, respectively.
Conclusion:
The gonadal shields are effective when placed exactly over the gonads but their dose reduction potential reduces drastically when the shields are displaced from the ideal location by as small as 4 cm.
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Taxonomy
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