第三代双源CCTA扫描体型特异性剂量估计的临床应用研究

Clinical Application of the Third Generation Dual Source CCTA Scan for Size-Specific Dose Estimation

目的探讨体型特异性剂量估算值(Size Specific Dose Estimation,SSDE)评估冠状动脉CT血管造影(Coronary CT Angiography,CCTA)辐射剂量临床应用的可行性。方法回顾性连续分析行CCTA 453例患者,均使用第三代双源Force型CT前瞻性心电门控触发轴扫。在设备上记录每个患者容积CT剂量指数(Volume CT Dose Index,CTDIvol)和DLP。所有病例图像数据再导入Radimetrics平台进行相关辐射剂量参数值的计算分析,包括器官剂量(皮肤、肺部、心脏)、有效剂量、患者水等效直径(Water-Equivalent Diameter,WED)以及SSDE。使用患者体型特异参数WED,按美国物理师协会220工作组报告的算法计算SSDE。然后计算SSDE与器官剂量的相关性,分别行SSDE、CTDIvol与器官剂量的线性相关分析。结果CTDIvol较SSDE低约22.4%(19%~24.8%),两者间差异有统计学意义(P<0.05)。SSDE与脏器剂量均为显著性正相关。SSDE与各器官剂量相关程度线性回归分析结果为:皮肤:P<0.001,r^(2)=0.96,斜率=0.13;肺部:P<0.001,r^(2)=0.93,斜率=0.70;心脏:P<0.001,r^(2)=0.95,斜率=0.94。CTDIvol与各器官剂量相关程度线性回归分析结果为:皮肤:P<0.001,r^(2)=0.94,斜率=0.16;肺部:P<0.001,r^(2)=0.89,斜率=0.94;心脏:P<0.001,r^(2)=0.94,斜率=1.25。通过WED校准的SSDE与器官剂量线性相关度高于CTDIvol。结论SSDE可应用于个性化评估第三代双源CCTA辐射剂量水平。

Objective To explore the feasibility of using size-specific dose estimation(SSDE)in the clinical application of Coronary CT Angiography(CCTA)radiation dose assessment.Methods Retrospectively analyzed 453 cases of CCTA.All cases were performed on the third generation dual-source Force CT with prospective ECG-gated triggered axial scan protocol.Volume CT dose index(CTDIvol)and DLP were recorded on the device for each patient.The image data were transferred to Radimetrics Workstation(Bayer)for radiation dose parameters computing,include organ dose doses(skin,lungs,heart),effective dose,patient water equivalent diameter(WED)and SSDE.SSDE was calculated using a patient-specific parameter,WED,as reported by AIST Working Group 220.Correlation between SSDE and organ dose were calculated respectively,and linear correlation analysis of SSDE,CTDIvol and organ dose was performed.Results CTDIvol was about 22.4%lower than SSDE(19%-24.8%),and the difference was statistically significant(P<0.05).There was significant positive correlation between SSDE and organ dose.Linear regression analysis of the correlation between SSDE and organ dose:skin:P<0.001,r^(2)=0.96,slope=0.13;lungs:P<0.001,r^(2)=0.93,slope=0.70;heart:P<0.001,r^(2)=0.95,slope=0.94.Linear regression analysis of the correlation between CTDIvol and organ dose:skin:P<0.00.1,r^(2)=0.94,slope=0.16;lungs:P<0.001,r^(2)=0.89,slope=0.94;heart:P<0.001,r^(2)=0.94,slope=1.25.The linear correlation between SSDE calibrated by water equivalent diameter and organ dose was higher than that of CTDIvol.Conclusion SSDE can be used to evaluate the dose level of the third-generation dual source CCTA.