Nuclear medicine practice in Japan: a report of the sixth nationwide survey in 2007

The Subcommittee on the Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to provide detailed information on its present status. Questionnaires were sent to all institutions known to the Japan Radioisotope Association to conduct nuclear medicine examinations. The questionnaires addressed the number and kind of nuclear medicine examinations performed as well as the kind and dose of the radiopharmaceuticals used during the month of June 2007. The annual number of total or specific examinations was then estimated. Of the institutions sent questionnaires, 1219 were for in vivo study, 49 for in vitro study, and 212 for positron emission tomography (PET) study. Of these, 92.2% provided answers. A total of 1569 gamma cameras were installed in 1119 institutions, of which 70% were dual-head cameras. The estimated total annual number of in vivo examinations expressed by the number of administered radiopharmaceuticals was 1.41 million, representing a decrease of 11.5% when compared with that of the previous survey (2002). The frequency of study with respect to single-photon emission computed tomography (SPECT) slightly increased to 42.3% from 39.9% in the previous survey. The most frequently performed scintigraphy was bone (38.3%), followed by myocardium (26.2%) and brain perfusion (14.1%). Brain perfusion scintigraphy slightly increased, whereas tumor scintigraphy decreased by one-half when compared with the previous survey. The most commonly used radiopharmaceutical for each scintigraphy was Tc-99m-HMDP for bone, thallium-201 (Tl-201)-chloride for myocardium, gallium-67 (Ga-67)-citrate for tumor, and technetium-99m-ethylcysteinate dimmer (Tc-99m-ECD) for brain. The number of PET institutes increased from 36 to 212. F-18-fluorodeoxyglucose (F-18-FDG)-PET dramatically increased 14.8-fold during the past 5 years. Radionuclide therapy also increased. I-131 therapy for thyroid cancer and hyperthyroidism was conducted yearly in 2373 and 4146 patients, respectively. A total of 13.1 million in vitro radioassays were carried out yearly, the number of which has been decreasing continuously since 1992. It was proved that the content of nuclear medicine practice in Japan has changed considerably in the past 5 years. Namely, F-18-FDG-PET and radionuclide therapy increased. This report might be useful for understanding the present trends of nuclear medicine practice in Japan.