上海市成年人胸部正位X射线摄影的剂量水平与分析

目的 掌握上海市成年人胸部后前位(正位)X射线摄影的剂量水平现状,分析影响剂量水平的主要因素.方法 用热释光剂量元件测量照射野中心的最大剂量(入射体表剂量).根据普通X射线机、计算机摄影设备CR和数字摄影设备DR 3大类设备数量及其在各级医院分布的比例,共测量1032名成年人在接受胸部正位X射线摄影时的入射体表剂量,并记录相应的主要摄影参数及相关信息.分析入射体表剂量均值与医院等级、设备类型以及主要摄影参数的差异情况.结果 上海市成年人胸部正位X射线摄影的入射体表剂量算术均值为0.23 mGy,其第75百分位数为0.28 mGy,小于我国目前推荐的诊断参考水平0.40 mGy.入射体表剂量均值与医院等级、设备类型以及常用摄影参数等显著相关.结论 与20世纪末相比,上海市成年人胸部正位X射线摄影的入射体表剂量水平下降明显,并存在可进一步下降的条件.

A survey and analysis of dose level for adults undergoing posteroanterior chest X-rays photography in Shanghai

Objective To survey the current dose level for adults undergoing posteroanterior (PA) chest X-ray photography in Shanghai, and to analyze the main factors affecting the dose level. Methods The thermoluminescence dosimeters (TLDs) were deployed to measure entrance surface dose (ESD) in the center of radiated fields. According to the numbers of three types of X-ray equipment and their distribution among different grade hospitals in Shanghai, the ESDs were surveyed for 1032 adults undergoing examination of PA chest X-ray photography from 2008 to 2010, and the relevant information was also recorded. The differences of the mean ESDs among different grade hospitals, equipment types and photographic parameters were statistically analyzed. Results The arithmetic mean of the ESDs for adults undergoing examination of PA chest X-ray photography in Shanghai was 0.23 mGy, and the 75th percentile value was 0.29 mGy, which were all below the current China diagnostic reference level (0.40 mGy). The averaged ESDs were significantly correlated with the grade of hospital, the equipment types and the photographic parameters. Conclusions Compared with the value in the last century, the ESD for adults undergoing PA chest X-ray photography in Shanghai obviously decreases, and there are the potentials for further reduction.