医用X射线诊断受检者放射防护最优化研究

Studies on optimization of radiation Protection for patients in diagnostic radiology

对于医学诊断中病人接受的剂量，个人剂量限值不适用，但放射防护最优化却可以发挥大的作用。本课题尝试将放射防护最优化的原理和方法运用于医学诊断的受检者防护，以期改善我国病人防护现状。调查以四川、山东和北京为重点调查区．为了最优化分析目的，本调查中将病人剂量划分为现实剂量、正当剂量和优化剂量三种类型，以便分别估计管理因素和设备因素对病人剂量的影响。调查结果显示出，目前我国医用Ｘ射线诊断受检者防护仍存在若干问题亟待解决，然而，只要采取适当的防护措施，降低病人剂量的前景是乐观的。例如，在不改变现有设备的条件下，只要采取适当的管理性措施，可使胸部透视和胸部摄影的病人剂量分别降低４０％和１８％；而采取某些设备性措施效果更为显著：胸部透视和胸部摄影，病人剂量可分别降低８２．４％和６６％，消化道检查降低８０％，若将胸部透视改为胸部摄影，并辅以其他必要的防护措施，病人的剂量可降低９１．７％。最优化分析证明，采取上述防护措施符合最优化原则。源－皮距；＊照射野面积表２调查地区各类Ｘ射线检查的Ｒ－Ｅ系数由于各调查地区Ｘ射线临床检查时实际使用的参数不尽相同，用此测定出的不同地区Ｒ－Ｅ系数之间存在一定差异。此外，由于实验中未对四川和山东?

For the exposure of patients in diagnostic radiology, individual dose limit does not apply, but optimization of radiological protection may play a major role.This project has been carried out on purpose to improve the protection of patients in medical diagnostic radiology in China,utilizing the principle of optimization.Taking Sichuan, Shandong and Beijing of China as surveyed areas,we investigated the present situation of protection of patients.In the survey.the patient dose was classified into practical dose,justified dose and optimized dose to evaluate the influences of managerial and equipment factors separately.The results show that there are some urgent protection problems in Xray protection in surveyed regions to be solved.This paper, however,points out that the prospects of reducing patient dose are encouraging provided that appropriate measures are adopted.For instance,taking proper managerial measures without radical change of existing equipment may reduce the patient dose in chest fluoroscopy and radiography by 40% and 18%, and refitting some equipment may reduce the dose respectively by 82.4% in chest fluoroscopy, 66% in chest radiography,and 80% in barium meal examination of gastrointestinal tract.Using chest radiography instead of fluoroscopy supplemented by other protective measures may reduce the dose by 91.7%.Optimization analysis shows that adoption of the above measures conforms to the principle of optimization of radiation protection .1.Laboratory of Industrial Hygiene,Ministry of Health,Beijing 100088,China;2.Institute of Radiation Medicine,Shandong Academy of Medical Sciences,Jinan 250001,China;3.Sichuan Institute of Radiation Health Protection,Chengdu 610041. China; 4.Beijing Institute of Radiation Health Protection,Beijing 100013, China.