Recent utilization of radiation and radioactivity in medical science

The application field of radiation and/or radioactivity to medical science and medical treatment, called radiology is considerably specialized recently. The clinical radiology is divided into three fields; (1) radiodiagnosis, (2) radiotherapy, (3) nuclear medicine. Positron emission tomography (PET) in nuclear medical science is a useful diagnostic technique. The x-ray computed tomography (CT) couldn't show a tumor beside skelton. The positron emission tomography, however, makes location of the tumor clear together with a nuclear medicine in which amino acid is labelled with radioisotope 11C. The metabolism of a focus is picturized by the PET. The blood flow in human brain is also picturized by using the PET together with a nuclear medicine in which carbon dioxide is labelled with 15O. Heavy Ion Medical Accelerator in Chiba (HIMAC) is a powerful installation for tumor treatment in radiotherapy field. National Institute of Radiological Science in Japan is carrying out clinical irradiation test of heavy ion (carbon ion). The pictures taken by the PET and the HIMAC are illustrated in the report. (M. Suetake)