マンモグラフィ撮影時の水晶体防護の検討─まぶたおよびフェイスガードによる効果の検討─

抄録

Purpose: In 2011, the International Commissionon Radiological Protection (ICRP) recommended reducing the threshold dose for the lens. Therefore, it is important to reduce the lens exposure dose in medical exposures. In a cranio-caudal (CC) view of mammography, the patient’ s lens receives scattered radiation. In this study, we investigated scatter dose around the lens during mammography and reviewed the simple and easy protection methods of the lens. Methods: Optically stimulated luminescence (OSL) dosimeters were placed in front of the device to obtain scattered radiation intensity distribution. The human phantom was placed in the same way as the CC positioning, and BR-12 phantoms with a thickness of 40 mm was placed on the FPD. Then, the scatter dose around the lens was measured using an OSL dosimeter. In order to confirm the change in the scatter radiation dose by the face guard (FG) and eyelid, we measured and compared under the same conditions the presence of FG and adipose tissue about 1 mm thick assuming the eyelid. Results: Scatter radiation intensity decreased around the FG. When the FG was installed, the scatter dose was reduced about 33%, and when the adipose tissue was pasted on the OSL dosimeter, the scatter dose was reduced about 29%. Conclusion: This study suggested that eye closure during mammography was effective in reducing lens exposure. In the future, we would like to expect further protective effects by increasing the thickness of FG and reviewing the materials.