SFOV对成人胸部CT水当量直径的体型特异性剂量估算的影响研究

Effect of SFOV on Water Equivalent Diameter of Size-Specific Dose Estimation in Adult Chest CT

目的探讨扫描野(Scanning Field of View,SFOV)对成人胸部CT水当量直径的体型特异性剂量估算(Water Equivalent Diameter of Size-Specific Dose Estimates,SSDE_(WED))的影响。方法回顾性分析2020年7至8月我院行胸部CT扫描的162例成人受检者,选取原始序列横断位中间层面图像,勾画圆形感兴趣区(Region of Interest,ROI),测量ROI的CT_(ROI)值、面积A_(ROI),记录受检者的性别、年龄、容积剂量指数(Volume CT Dose Index,CTDI_(vol))、剂量长度乘积(Dose Length Product,DLP)和SFOV的数值,计算每例受检者中间层面的水等效直径(Water Equivalent Diameter,WED)、转换因子(f_(size·WED))和SSDE_(WED)。利用多元回归分析性别、年龄、CT_(ROI)、A_(ROI)、CTDI_(vol)、DLP和SFOV与SSDE_(WED)的相关性。结果性别、年龄、A_(ROI)、CTDI_(vol)、DLP和SFOV与SSDE_(WED)有显著差异(P<0.05),CT_(ROI)与SSDE_(WED)无显著差异(P>0.05),多元回归分析SSDE_(WED)与SFOV呈0.06倍正线性相关。结论SFOV对成人胸部CT的SSDE_(WED)影响较大,且呈0.06倍正线性相关,在临床扫描中精准调节SFOV可以降低成人受检者胸部CT辐射剂量。

Objective To investigate the effect of scanning field of view(SFOV)on water equivalent diameter of size-specific dose estimates(SSDE_(WED))in adult chest CT.Methods A total of 162 adult patients who underwent chest CT scan in our hospital from July to August in 2020 were retrospectively analyzed.The middle level images of the original sequence were selected,and the circular region of interest(ROI)was drawn.The CT value and area of ROI were measured.The gender,age,volume CT dose index(CTDI_(vol)),dose length product(DLP)and SFOV were recorded.The water equivalent diameter(WED),f_(size·WED)and SSDE_(WED)in the middle layer of each patient were calculated.Multiple regression analysis was used to analyze the correlation between gender,age,CT_(ROI),A_(ROI),CTDI_(vol),DLP,SFOV and SSDE_(WED).Results Gender,age,A_(ROI),CTDI_(vol),DLP and SFOV were significantly different from SSDE_(WED)(P<0.05),but CT_(ROI)were no significantly different from SSDE_(WED)(P<0.05).Conclusion SFOV has a significant influence on the SSDE_(WED)of chest CT scan,with a positive linear correlation of 0.06 times.Precisely adjusting SFOV can reduce the chest CT radiation dose of adult patients in clinical scan.