上海市2007年X射线诊断的医疗照射剂量水平

[目的]掌握当前上海市各主要类型x射线诊断检查的剂量水平。[方法]根据x射线诊断设备种类、应用发展趋势及医院级别的差异，分别抽查约3％的普通x射线机和约25％的计算机X射线摄影、数字化X射线摄影以及x射线计算机断层扫描（x—cT）机，通过布放热释光剂量计测量成年人在不同检查方式和体位的入射体表剂量；利用标准的X—CT剂量模体和电离室测量不同扫描条件下的CT剂量指数，进而估算受检者的有效剂量。[结果]X射线摄影所致受检者的入射体表剂量平均值的变化范围为0．13～4．35mGy，其中手部摄影最低、腰椎侧位摄影最高。胸部透视时胸部表面的平均剂量为3．79mGy。胆囊和尿路造影以及上消化道钡餐和钡灌肠检查的受检者上腹部体表的平均剂量最大，分别为30．24、30．97、25．28、23．02mGy；消化道钡餐检查时胸部体表的平均剂量为24．27mGy，钡灌肠检查时下腹部体表的平均剂量为21．62mGy。头部X-CT扫描时受检者的平均有效剂量为（0．58±0．22）mSv，体部x—CT扫描时受检者的平均有效剂量为（5．18±1．92）mSv。[结论]较全面地得到了当前上海市主要类型x射线诊断所致受检者的剂量水平，可为推动进一步完善x射线诊断的医疗照射指导（参考）水平和加强受检者防护提供重要资料。

Dose Levels of Medical Exposure from Diagnostic X-ray Examinations in 2007 in Shanghai

[ Objective ] To grasp the current dose levels for the main types of diagnostic X-ray examinations in Shanghai. [ Methods ] According to the types of X-ray equipments and their application trend as well as the hospital-grade distribution, about 3% of the conventional X-ray equipments and about 25% of the computed radiography （ CR ）, digital radiography （ DR ） and X-ray computed tomography （ X-CT ） equipments were selected for survey. The thermoluminescence dosimeters （ TLDs ） were deployed to measure the entrance surface doses （ ESDs ）for adults undergoing different ways and positions of X-ray diagnoses. The effective doses of examinees undergoing different parts of X-CT scans were estimated based on measurements of X-CT dose indices through the dose phantom and ionization chamber. [ Results ] The average ESDs of X-ray photography ESDs changed from 0. 13 mGy to 4.35 mGy, in which the lowest was with the hand photography, and the maximum was with the lateral lumbar spine photography. The average ESD on chest for chest fluoroscopy was 3.79 mGy. The largest ESDs for examinations of gall bladder, urinary tract, upper gastrointestinal barium meal and barium enema were found on the upper abdomen, with the averages of 30.24, 30.97, 25.25 and 23.02 mGy, respectively. Furthermore, the average ESI） on chest for upper gastrointestinal barium meal examination was also as high as 24.27 mGy, and the value on lower abdomen undergoing barium enema examination was 21.62 mGy. The average effective dose for head X-CT scans was （ 0.58±0.22 ）mSv, and the value of body X-CT scans was（ 5.18±1.92 ）mSv. [ Conclusion ] The current dose levels for main types of diagnostic X-ray examinations in Shanghai were more comprehensively grasped through this survey. The results provide important background information to promote the establishment of reference dose levels for diagnostic X-ray examinations, and to strengthen the radiation protection for examinees.