婴儿头颅CT中铋屏蔽对辐射剂量和影像质量的影响  

Effect of bismuth shielding for eye-lens in infant head CT on radiation dose and image quality

作　　者：戈明媚[1] 吴冰[1] 陈华[1] 赵倩[1] 冯泽臣[2] 张泓[2] 于宏伟[1] 张宗丽[1] 杜国生[2] 

机构地区：[1]北京军区总医院放射诊断科,100700 [2]北京市疾病预防控制中心

出　　处：《中华放射医学与防护杂志》2013年第6期668-670,共3页Chinese Journal of Radiological Medicine and Protection

摘　　要：目的 研究婴儿头颅CT检查中使用铋屏蔽材料降低眼晶状体受照剂量的效果及对图像质量的影响。方法 使用适合患儿使用的自制铋屏蔽防护眼罩、婴儿体模，采用热释光探测器测量受照剂量。CT扫描条件选择120 kV、130 mA轴位扫描，分别进行铋屏蔽和无屏蔽两组模体测试，比较模体内相当于晶状体位置的受照剂量；应用同样CT扫描参数，对临床疑为颅内出血的99例患儿佩戴铋屏蔽眼罩后进行头部扫描，由2名高年资医生分别进行图像质量评估，并比较评分的一致性。结果 体模实验显示，无屏蔽时眼罩后方区域吸收剂量为25 mGy，经铋防护眼罩屏蔽后眼罩后方的吸收剂量为17 mGy，降低辐射剂量32%。佩戴铋屏蔽眼罩对患儿头部CT图像质量无明显影响。结论 在婴儿头颅CT扫描中使用铋屏蔽防护眼罩，可明显降低眼晶状体放射吸收剂量，同时对CT图像质量的影响是可接受的。Objective To explore the benefit from eye-lens dose reduction and the impact on the clinical imaging quality using orbital bismuth shield in infant head CT. Methods According to the width and length of the patients＇ eyes, the eye-shield was modified for infant sizes. An infant head CTDI phantom was scanned twice with and without eye-lens bismuth shielding. The infant CT head protocols were 120 kV, 130 mA with axial sequential scanning. The thermoluminescence detectors （TLD） were used to detect the organ dose of eye lens. Ninety-nine infant cases clinically suspected intracranial hemorrhage were scanned with the same CT scanning protocol. Two senior radiologists scored the image quality and evaluated the consistency of scores. Results The radiation dose for eye-lens was reduced by 32% on phantom test. The rate of accepted imaging was 92% and κappa value between two radiologists was 0.78. Conclusions The eye-shield could reduce doses to eye-lens significantly in infant head CT scanning with acceptable image quality.

关 键 词：铋屏蔽 头颅CT 辐射剂量 婴儿 眼晶状体 

分 类 号：R142[医药卫生—公共卫生与预防医学]