降低儿童颞骨CT扫描辐射剂量的临床研究

The study of reducing the radiation dose in children temporal bone CT

目的:探讨颞骨CT扫描时降低毫安值对受检者受到的辐射剂量及图像质量的影响,并比较螺旋扫描与非螺旋扫描方式的辐射剂量及图像质量。方法:选择行颞骨CT扫描的患儿60例,分别采用螺旋及非螺旋扫描各30例,每种扫描方式又分为常规剂量(120kV、150mA)组和低毫安(120kV、60mA)组各15例。扫描时记录容积CT剂量指数(CTDIvol/CTDIw)、扫描长度,并计算出平均剂量长度乘积(DLP);对不同扫描参数的图像质量进行评分及统计学分析。结果:在同一扫描方式下,低毫安组的辐射剂量明显低于常规剂量组(P<0.01),而两组的图像质量无明显差异;在同一毫安值时,轴位螺旋扫描方式的辐射剂量明显低于非螺旋扫描方式(P<0.01),而两种扫描方式的图像质量无明显差异。结论:低毫安、螺旋扫描方式能够显著降低颞骨CT检查时的辐射剂量,且又能保证图像质量,满足临床诊断的需要,可在儿童检查中推广。

Objective：To study the effect of reducing mA or kV on the quality of image and the radiation dose of the patients when undergoing temporal bone CT.To compare the radiation dose and image quality between spiral and non-spiral Temporal bone CT scan.Methods：Four groups of 15 patients each underwent temporal bone CT using spiral and non-spiral scan.The different parameters were following：120 kV and 150mA,or 120 kV and 60 mA respectively.The volume CT dose index （CTDIvol/CTDIw） and calculated the average dose-length produce （DLP）were recorded.Image quality of those four groups was compared and scored by two radiologists,and SPSS was uesed to calculate the result.Image quality was evaluated for the anatomical structures,including cochlea,semicircular canal,auditory ossicle,the facial nerve canal,tympanic tegmen.Results：At the same scan mode,the radiation exposure of the low-mA scaning was significantly reduced comparing with non-spiral（P0.001）.Using the same mA,the radiation dose in axial spiral was obviously lower than that of non-spiral（P0.001）.No difference was found of the quality of image betwwen group of low mA and conventional scanning.The quality of image with spiral-scan was much higher than that of non-spiral scan.Conclusions：Compared with non-spiral CT,the low-mA temporal bone spiral-CT technology might decrease the radiation exposure and guarantee the image quality to meet the need of clinician.