Bone scintigraphy with sup(99m)Tc-pyrophosphate

Basic and clinical investigation was carried out on the sup(99m)Tc-pyrophosphate kit prepared for detect 2-8 metastatic bone tumor. In basic investigation, purity and stability of the prepared sup(99m)Tc-pyrophosphate were examined by paperchromatography. The distribution within the body and accumulation ratio of it in the bone to that in each tissue were studied in rat, and excretion rate in the urine was studied in the patients with normal renal function. While in clinical investigation, accumulation ratio was examined by using scinticamera in 37 patients with various bone diseases, and the detectability was compared between bone scintigram and X-ray. sup(99m)Tc-pyrophosphate was revealed to be easily prepared by this kit, to have excellent chemical purity and stability, to be rapidly excreted in the urine after intravenous injection and to draw the urinary system markedly. As only a small amount of it was accumulated in the tissues other than the bone except the urinary system, a skeletal image was clearly visualized. The energy of γ-ray in sup(99m)Tc was so low that the bone scintigram was easily affected by the direction of scanning. The scintigraphy was most effectively performed about 3 hours after intravenous injection, and the accumulation ratio in the lesion to that in the normal bone was 1.1 to 23.1 at that time, showing a clear and positive picture of the lesion. However, it could not differentiate malignant bone lesion from benign one. (Kanao, N.)