目的比较不同低剂量多层螺旋 CT扫描在儿童头部检查中获得的图像质 量，建立合适的儿童头部低剂量扫描条 件，寻找达到临床诊断要求的同时减少患 儿接受的放射剂量。方法 前瞻性地将90 例儿童头部外伤后16层螺旋CT平扫检查 的患者随机分为三组：常规剂量组30例 (120Kv，250mAs)、低mAs组30例(120Kv， 150mAs)和低Kv低mAs组30例(90Kv， 150mAs)，由3名副主任医师职称以上的放 射科医生在不知三组CT扫描条件的前提下 对三组CT图像质量进行评估，分优、良和 差三个等级。结果 三组不同CT剂量扫描 参数获得的CT图像质量优良率无统计学差 异(p＞0.05)，均可满足临床诊断需求。 结论 低Kv低mAs组(90Kv，150mAs)的CT检 查图像质量既可满足临床诊断要求，又可 减少儿童头部接受的辐射剂量。

Objective To compare the different low-dose multislice CT image quality in the examination of the children's head for the establishment of appropriate low-dose scan parameters, in order to reduce radiation dose in the clinical diagnosis. Methods 90 children of head CT examination prospectively were randomly divided into three groups:the conventional dose group of 30 children (120Kv,250mAs), low mAs group of 30 children (120 Kv,150mAs), low mAs and low Kv group of 30 children (90 Kv,150mAs). The analysis of head CT image quality in the three groups was done by three radiologists. Results CT image quality of the head with different scan parameters in the three groups could meet the diagnostic requirements. There was no significant difference among the three CT image quality (p＞0.05). Conclusion CT image quality with low mAs and low Kv (90 Kv,150mAs) can meet the requirements of clinical diagnosis while reducing the dose of radiation.