【摘要】 本文报道了北京市 X 线诊断检查所致公众剂量的估算方法和结果。通过分层抽样调查,取得了北京市1983年各种 X 线诊断检查的年频率及其随年龄和性别的分布。用自制的可布放25—106个热释光剂量计〔LiF(Mg,Cu,P)〕的专用衣,测量了各种 X 线诊断所致受检者的平均体表照射量。用切刈为17层、在16个器官(或组织)中布放267个热释光剂量计的人体模型进行模拟照射实验,得到了各种 X 线诊断检查所致受检者平均体表照射量与平均器官吸收剂量间的转换系数。采用的加权剂量当量,考虑了性别之差别。所得主要结果如下:(1)1983年北京市居民 X 线诊断检查的总年频率为671.7人次/10~3人,其中胸部透视和消化道检查分别占67.6%和1.9%。(2)北京市居民 X 线诊断检查年频率按受检者性别、年龄的分布。总频率中男性占51.5%,女性占48.5%,检查频率高峰出现在20—39岁的几个年龄组中。(3)37种 X 线诊断检查所致受检者的平均体表照射量及其分布情况。(4)北京市各种 X 线诊断检查所致受检者的平均体表照射量与器官吸收剂量的转换系数(以mGy/R表示),由人体模型模拟照射实验所得到的这些系数可用于相应条件下的剂量估算。(5)北京市平均每次 X 线诊断检查所致受检者的器官吸收剂量和加权剂量当量。(6)北京市 X 线诊断检查所致公众总集体更多还原

【Abstract】 This Paper describes the methods and results of the estimat-ion of population doses due to medical diagnostic X-ray examinations inBeijing.According to the sampling requirements for statistics,the freque-ncy of medical diagnostic X-ray examinations of the residents in Beijingcity(including both urban and suburban areas)was investigated,and thedose monitoring of the examinees were carried out.Human Phantom expe-riments simulating irradiation conditions were completed.Highly sensitiveLiF(Mg,Cu,)Pthermoluminesent dosimeters made in our Institute wereused in the investigation of surface exposure and their distribution inexaminees and in the simulation experiments.In consideration of thespecific characteristics of distribution of sex and age among the examine- es,the weighting factors which we have adopted in estimating the weig-hted dose equivalent are different from those recommended in ICRP Pub-lication 26.The results of this study are as follows:(1)The total annual frequency of X-ray diagnestic examinations ofthe residents in Beijing obtained in 1983 is 671.7 examinations per 1000population of which chest X-ray fluoroscopy and digestive tract exami-nations account for 67.6% and 1.9%,respectively.(2)The annual frequency distribution of diagnostic X-ray examinat-ions for sex and age of examinees is given in this paper of which 51.1%are males and 48.5% females.Peaks of frequency appear several groupsbetween 20 and 39 years of age.(3)The average body surface exposures and their distribution inexaminees by 37 types of diagnostic X-ray examinations are given.(4)The conversion factors(in mGy/R)between average surfaceexposures of examinees and absorbed doses of organs were obtained.Thesefactors,obtained from the simulated experiments with phantom,can beused in dose estimation under corresponding conditions.(5)The absorbed doses of organs and the whole body weighteddose equivalents of examinees per X-ray examination in Beijing are given.(6)The total collective weighted dose equivalent of residents inBeijing from diagnostic X-ray examinations is 3631 man·Sv/a or 393man·Sv/a in one million Persons.of the total PoPulation dose 38.8%come from digestive tract examination,33.1% from chest fluoroscopy and9.0% from lumbar spine examination.The annual weighted dose equivalentaccording to the number of people in Beijing city is 0.39 mSv.(7)The genetically significant dose(GSD)from X-ray examinationsis 0.09 mGy/a.The main portion of GSD is Caused by the examinatiosnof hip and upper femur,pelvis,lumbosacral spine etc.(8)Per caput mean bone marrow dose(CMD)is 0.22 mGy/a.Chestfluoroscopy is the prime contributor to CMD.The results mentioned above are useful to improving radiation protect-ion of examinees and considering whether a diagnostic X-ray procedure isjustified or should be optimized.The information derived from this surveyis also helpful to calculating dose level of medical exposure and promotingreasonable use of X-ray examination.更多还原