低剂量螺旋CT扫描技术在儿童胸部病变中的应用探讨

Use of low-dose spiral CT in children with chest disease

目的优化儿童肺部CT曝光参数,在不影响影像诊断的前提下,尽可能降低辐射剂量。方法 157个疑有胸部病变的儿童按扫描条件被分为四组:A组,普通扫描组,35例,扫描参数与普通成人相同;B组,低管电流组,38例,管电流为30mAs,其他扫描条件与普通组相同;C组,低电压组,52例,管电压为80kV,其他条件与普通组相同;D组,低电压及低电流组,32例,管电流为30mAs,管电压为80kV,其他扫描条件与普通组相同。观察各组的成像质量,并分析CT剂量加权指数CTDIvol及剂量长度乘积DLP。结果从A到D组图像质量呈逐渐下降的趋势,其中A、B以及C组的图像质量不影响诊断,而D组的CT图像伪影较多,易造成误诊;各组的CT剂量加权指数以及剂量长度乘积亦呈逐渐下降趋势。结论采用低剂量螺旋CT扫描技术进行儿童胸部扫描,即可保证影像诊断,又可适当地降低曝光量,减少其辐射危害,具有十分重要的临床价值。

Objective To investigate the optimal low-dose CT parameters for children with chest diseases. Methods One hundred and fifty-seven children were divided into four groups and evaluated using regular scanning parameters （group A, 35 cases）, 30 mAs （group B, 38 cases）, 80kV（group C, 52 cases）, 40 mA and 80kV（group D, 32 cases）. The image quality, CT dose weighted index （CTDIVOL） and dose length product （DLP） were analyzed. Results The image quality, CTDIvol and DLP decreased progressively from groups A to D group. The images of groups A to C were diagnostic whereas the image artifacts in group D may compromise the diagnosis. Conclusion Low--dose spiral CT scan of the chest can reduce radiation exposure to children without compromising imaging diagnosis.