低剂量CT扫描结合迭代算法重建行颞骨成像

Radiation dose optimization in temporal bone CT with iterative reconstruction technique

目的:探讨颞骨低剂量CT扫描结合迭代算法(iDose 3)行颞骨成像的可行性及其最佳参数。方法:以成年尸头为研究对象,应用飞利浦256层CT,采用螺旋扫描模式,分别在电压120kV、100kV和80kV时用不同的管电流时间乘积进行颞骨扫描,从250mAs开始,间隔30mAs逐次降低,直至图像较差不能满足诊断时终止扫描,重建算法采用iDose level 3,滤过函数Y-sharp(C)。两位医生采用5分制评分标准对16个解剖结构进行评估。比较所有图像的图像质量及辐射剂量。结果:"100kV+70mAs+iDose level 3+Y-sharp(C)"的成像组合是良好显示解剖结构的最低剂量组合,有效剂量约0.15mSv。结论:颞骨低剂量扫描切实可行,"100kV+70mAs+iDose level 3+Y-sharp(C)"是最低剂量扫描方案。

Objective：To evaluate the feasibility and the optimal parameters for imaging of the temporal bone by using low-dose-256-slice CT with iterative reconstruction technique（IRT）（iDose 3）.Methods：One exsomatized cadaveric head was scanned with spiral scanning mode on 256-slice CT scanner from Philips.Three levels of tube tensions from 120kV to 80kV were chosen for the temporal bone scan.At every tube tension,multiple current-time products were used from 250mAs to 70mAs in 30mAs successive interval decrease.Reconstructions were employed by using IRT （iDose Level 3）and edge-enhangcing reconstruction kenel Y-sharp（C）.The visibility of 1 6 anatomical landmarks was scored using a five-point-quality rating.The image quality and radiation dose of every level were assessed.Results：The protocols of＆quot;100kV＋70mAs＋iDose level 3＋Y-sharp （C）＆quot;can clearly depict the normal anatomy,and the radiation dose is lower than the other else, with effective dose of about 0.15mSv.Conclusion：Low-dose-256-slice CT with IRT is feasible for temporal bone scanning with sufficient anatomical detail.The protocols of＆quot;100 kV＋70 mAs＋iDose level 3＋Y-sharp（C）＆quot;are the optimized ima-ging protocols.