Nagaoka Hiroaki, Watanabe Hiroshi, Yamaguchi Ichiro, Fujibuchi Toshioh, Kida Tetsuo, Tanaka Shinji
Iwate Medical University Hospital.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2009 Dec 20;65(12):1644-9. doi: 10.6009/jjrt.65.1644.
A clearance system for medical radioactive solid waste has not yet been implemented in Japan. Since 2004 new regulations have allowed institutions using positron emission tomography(PET)to handle totally decayed radioactive waste as non-radioactive waste after decay-in-storage. It was expected that this new regulation would mediate the installation of clearance systems in Japan. In order to assess the current situation of radiation safety management in PET institutions, we conducted a nationwide survey.
The study design was a cross-sectional descriptive study conducted by questionnaire. The subjects of this survey were all the PET institutions in Japan. Among 224 institutes, 128 institutes are equipped with cyclotrons and 96 institutes are not. The number of returned questionnaires was 138.
Among institutes that are using delivered radiopharmaceuticals, 80% treat their waste as non-radioactive according to the new regulation. The impact of new regulations for reducing radioactive waste in PET institutes without a cyclotron was estimated at about $400 thousand per year.
The main concern of medical institutes was assessment of the contamination caused by by-products of radioactive nuclides generated in target water during the operation of a cyclotron. It was thought that a rational rule based on scientific risk management should be established because these by-products of radioactive nuclides are negligible for radiation safety.
New regulation has had a good influence on medical PET institutes, and it is expected that a clearance system for medical radioactive waste will be introduced in the near future, following these recent experiences in PET institutes.
日本尚未实施医用放射性固体废物的清除系统。自2004年起，新规定允许使用正电子发射断层扫描（PET）的机构在储存衰变后将完全衰变的放射性废物作为非放射性废物处理。预计这一新规将促使日本安装清除系统。为评估PET机构辐射安全管理的现状，我们开展了一项全国性调查。
本研究设计为通过问卷调查进行的横断面描述性研究。本次调查的对象为日本所有的PET机构。在224家机构中，128家配备了回旋加速器，96家未配备。回收问卷138份。
在使用已交付放射性药物的机构中，80%根据新规将其废物作为非放射性废物处理。据估计，新规对未配备回旋加速器的PET机构减少放射性废物的影响约为每年40万美元。
医疗机构主要关注的是回旋加速器运行期间靶水中产生的放射性核素副产品所造成的污染评估。由于这些放射性核素副产品对辐射安全的影响可忽略不计，因此认为应建立基于科学风险管理的合理规则。
新规对医用PET机构产生了良好影响，预计在PET机构近期这些经验之后，医用放射性废物清除系统将在不久的将来引入。
