Evaluation of Elasticity, Dose Reduction, and Image Quality on Sr-Pb Shield for Thoracic CT Examination

Abstract

The performance of chest CT always involved the scanning of breast since it was positioned within the scan range. It makes this organ always receives an amount of radiation that potentially harms the biological system. Many attempts have been performed to reduce the radiation doses objected to breast, including the utilization of radio-protective shield. This study aims to develop the radio-protector shield silicon rubber (SR) - Lead (Pb) based for the breast. The shield was developed with a thickness of 0.6 mm and SR:Pb ratios of 100:0, 98:2, 96:4, 94:6, and 92:8. After that, the shield was placed over an anthropomorphic phantom. The shield’s reliability was tested in terms of elasticity, radiation dose, and image quality. The elasticity level of a material was indicated by Young's modulus yielded. Our results showed that the Young's modulus decreased as the percentage of Pb increased. Breast surface dose was measured using a Radcal ion chamber on the surface of the breast phantom. The measured dose was reduced as Pb increased, the dose using shielding at the highest percentage of 92:8 wt% is 8.71 mGy. The measured SNR without using shielding is 18.38, while the measured SNR using shielding 100:0, 98:2, 96:4, 94:6 and 92:8 was 18.47; 17.45; 16.65; 15.49, and 14.23, respectively. SR-Pb shielding has a Young’s modulus less than 0.035 GPa and can cover the chest of phantom well. SR-Pb shield was able to reduce the breast dose by 26% while the image quality in all variations of the SR:Pb ratio was above the rose criterion value with an insignificant decrease.