Difficulty in the usage of nuclides in hospitals

In Japan, the uses of radioisotopes in hospitals are increasing year after year. Therefore, the problems of the treatment and disposal of radioactive wastes are important. The liquid and gaseous wastes with radioactivity concentrations below the maximum permissible levels are allowed to be disposed of on the sites by the law. However, high-level liquid wastes and solid wastes cannot be disposed of on the sites. These wastes stored in steel drums are collected by Japan Radioisotope Association, and finally treated and disposed of on the site of Japan Atomic Energy Research Institute. The nuclides used in hospitals are principally Tc-99m, and also 131I, 198Au, 125I and 3H. The following matters are described: the present situation, radioactive wastes from medical treatments, and the management of radioactive solid, liquid and gaseous wastes from hospitals. (J.P.N.)