Ota J, Yokota H, Takishima H, et al. - Because organ-effective modulation (OEM) is a mechanism for lowering radiation dose in selected organs on CT, researchers measured breast radiation dose in Asian patients undergoing chest CT and clarified the degree of reduction in exposure. Sixty female patients undergoing non-contrast chest CT after breast cancer surgery were randomly selected. Using a phantom and an ionization chamber dosimeter, the effects of angle and object size were measured to clarify the characteristics of OEM. According to results, the OEM group received 9.1 ± 1.9 mGy and the non-OEM group received 10.7 ± 2.4 mGy. It was noted that OEM reduced the exposure by 12.2%. Findings suggested that OEM is a helpful mechanism to reduce breast exposure to radiation without influencing the quality of diagnostic imaging. The rate of reduction was negatively associated with body habitus.