Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography

Abstract

Background Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated. Methods Radiation doses from CCTA to critical organs were determined using metal-oxide-semiconductor field-effect transistors positioned in a customized anthropomorphic whole-body dosimetry verification phantom. Image noise and signal were measured in regions of interest (ROIs) including the coronary arteries. Results With bismuth shielding, breast radiation dose was reduced 46–57% depending on breast size and scanning technique, with more moderate dose reduction to the heart, lungs, and esophagus. However, shielding significantly decreased image signal (by 14.6 HU) and contrast (by 28.4 HU), modestly but significantly increased image noise in ROIs in locations of coronary arteries, and decreased contrast-to-noise ratio by 20.9%.. Conclusions While bismuth breast shielding can significantly decrease radiation dose to critical organs, it is associated with an increase in image noise, decrease in contrast-to-noise, and changes tissue attenuation characteristics in the location of the coronary arteries.

Prevalence of Protective Shielding Utilization for Radiation Dose Reduction in Adult Patients Undergoing Body Scanning Using Computed Tomography

“…9,11 Despite these striking numbers, radiation shielding has been a topic of debate in the literature. 32 Some studies have indicated an increase in image noise in the area directly underlying the protective shield 31,33,34 ; in contrast, other studies indicate no significant effect on diagnostic image quality. 7,8,35 Radiation shields can be placed either over the area being studied and thus in the path of the radiation beam (i.e., ''in-plane'' shielding), or placed over areas outside of the …”

Radiation Biology Irradiator Dose Verification Survey

“…Simple physical phantoms, often just slabs of tissue equivalent material, are still critical for standardization procedures; however, anthropomorphic phantoms, which mimic the human body in shape and heterogeneous density distribution, receive significant usage especially in analysis of dose delivery to specific organs (16)(17)(18)(19)(20). The widespread usage of small animal models has spurred development of physical phantoms of mice as well.…”

Application of Different methods for Reducing Radiation Dose to Breast during MDCT

“…[28]. Einstein et al (2011) reported that bismuth shielding decreased breast dose during coronary CT angiography by 46%-57% depending on breast size and scanning protocol [29]. Jia Wang (2011) reported that bismuth shielding reduced breast dose by 37% [18].…”