[en] In the period from January to December 1978, the NIRS-Chiba isochronous cyclotron has been used regularly for medical and biological purposes, i.e. clinical trial of fast neutron therapy, radiobiology and production of short-lived radioactive nuclides. Reporting the activities during the period, the following are given: features of the year, machine research and improvement, partition of machine time, radiation doses received by personnel, principal particulars of cyclotron, personnel, and publications. (Mori, K.)