体型特异性剂量评估在估算外伤儿童胸腹部CT扫描辐射剂量中的准确性研究

Accuracy of SSDE in Estimating Radiation Dose of Thoracic and Abdominal CT Scanning in Traumatic Children

目的比较容积CT剂量指数(Volume CT Dose Index,CTDIvol)与体型特异性剂量估算值(Size-Specific Dose Estimate,SSDE)在估算外伤儿童胸腹部CT扫描辐射剂量中的差异并探讨其临床应用。方法前瞻性选取胸腹部CT检查的0~16岁患儿87例。根据胸部有效直径(Effective Diameter,ED)将所有患儿分为A1、B1、C1三组;根据腹部有效直径(ED)将所有患儿分为A2、B2、C2三组。CT扫描后,对患儿的图像质量进行主观及客观评价。记录患儿的CTDIvol,计算得到SSDE,对比分析两者间的差异,并计算SSDE较CTDIvol的增量(X)。结果 A1组、B1组和C1组在SNR、SD及ED间差异均有统计学意义(P<0.05)。A2组、B2组和C2组在SNR、SD及ED间差异均有统计学意义(P<0.05)。各组患儿胸、腹部图像质量主观评价结果差异有统计学意义。A1、B1和C1三组患儿组内X值分别为76.9%、34.8%和-13.2%,均具有统计学差异(P<0.005)。A2、B2和C2组内X值分别为52.6%、20.7%和-11.1%,均具有统计学差异(P<0.005)。结论 SSDE能精确评估不同体型的患儿胸腹部CT检查时受到的辐射剂量。

Objective To compare the difference between volume CT dose index(CTDIvol) and size-specific dose estimate(SSDE) in estimating the radiation dose of chest and abdomen CT scan in children with trauma, and to explore its clinical application. Methods A total of 87 children aged from 0 to 16 were prospectively enrolled for thoracic and abdominal CT examination. According to the effective diameter(ED) of the chest, all children were divided into three groups: A1, B1 and C1;according to the effective diameter(ED) of the abdomen, all children were divided into another three groups: A2, B2 and C2. After CT scannig, the image quality of children was evaluated subjectively and objectively. CTDIvol were recorded, and SSDE were calculated. The difference between the two parameters was analyzed and the increment(X) of SSDE compared with CTDIvol was calculated. Results There were significant differences(P<0.05) in SNR, SD and ED among group A1, B1 and C1. There were significant differences(P<0.05) in SNR, SD and ED among group A2, B2 and C2. There was significant difference in subjective evaluation of thoracic and abdominal image quality. The X values of A1, B1 and C1 groups were respectively 76.9%, 34.8% and-13.2%, with statistical difference(P<0.005). The X values of A2, B2 and C2 groups were respectively 52.6%, 20.7% and-11.1%, with statistical difference(P<0.005). Conclusion SSDE can accurately assess the radiation dose of thoracic and abdominal CT in children with different figures.