[en] In fiscal year 1986, this Institute was alloted the budget of 6.4 billion yen, 16 % more as compared with the previous year. It was for promoting the various facilities for internal exposure experiment, the basic design of a heavy particle beam cancer treatment apparatus, the additional construction of the cyclotron building and other various works. As the research activities, the results of high level were obtained in four special researches on tritium, probabilistic effect, exposure evaluation and heavy particles. The case of neutron therapy has reached 1500 cases, and the adaptation to the therapy became clearer. The 14th environment seminar was held in December with the title 'Dynamic analysis of contamination mechanism in marine living things'. Also the 18th symposium on 'New development in chromosome research' was held. Due to the Chernoby1-4 accident on April 26, the medical examination of the travelers to USSR was carried out at international airports, and the report was made. As the program of the Regional Cooperation Agreement of IAEA, the training course for radiation therapy and the cooperation with the research on the diagnostic techniques of nuclear medicine were carried out. 39 personnel carried out international activities, and 63 foreign researchers visited the Institute. (K.I.)