目的 研究256层iCT个性化 胸部低剂量扫描方案。方法 选取150 名受检者，基于BMI指数(kg/m2)分为 三组：A组(BMI<18.5，n=50)、B组 (18.5≤BMI≤25，n=50)和C组(BMI>25， n=50)，分别采用30mAs、45mAs及60mAs 进行胸部CT扫描，三组扫描数据均采用 FBP及iDose4对图像进行重建。比较各组 间辐射剂量、CT图像噪声(SD)以及主观 图像质量。结果 三组采用iDose4迭代 重建的图像质量均可满足诊断要求。A 组、B组和C组的有效剂量(ED)均值分别 为(0.33±0.06)mSv、(0.52±0.12)mSv 和(0.91±0.24)mSv。结论 应用iDose4 迭代重建技术，基于受检者的BMI，可获 得满意的个性化、低剂量胸部CT扫描方 案。

Objective To study scanning scheme in individuation and low dose chest CT using 256-slice iCT. Methods 150 patients were assigned into three groups according to body mass index(BMI):Group A (BMI<18.5, n=50, 30mAs), group B(18.5≤BMI≤25, n=50, 45mAs) and group C (BMI>25, n=50, 60mAs), Images were reconstructed by FBP and iDose4 respectively. Quantitative noise, subjectively image quality, and radiation dose were compared and analyzed statistically. Results The images reconstructed by iDose4 of each group were acceptable. The average ED for group A, B and C was (0.33±0.06)mSv, (0.52±0.12)mSv and (0.91±0.24)mSv, respectively. Conclusion Application of iDose4 iterative reconstruction technique based on BMI can achieve satisfactory scanning scheme in individuation and low dose chest CT.