Clinical technique decreasing the exposure dose in patients of having radionuclide study

99mTc-methylene diphosphonate (99mTc-MDP), which is excreted through the urinary tract and partly accumulated on the content of bladder, is the most common radiopharmaceutical form among the current bone scintigraphy. In order to find the methods for decreasing the exposure of the whole body and the bladder, 15 patients were selected for the present study. None of the patients had renal disorder, or abnormality increased radionuclide uptake over the whole bones. They were divided into two groups; i. e. 10 patients were forced to take fluid during examination and the other 5 patients were order not to take fluid. After administration of 99mTc-MDP, whole body activity was compared in the 2 groups. At the same time, exposure of patients' wall of the bladder was estimated from their urine activity. Forced fluid intake group received less radioactive exposure to the whole body than no fluid intake group did. For the forced fluid intake group, it is estimated that exposure of the wall of bladder can be reduced about 40% if one avoids urine in 50 minutes after administration of 99mTc-MDP instead of avoiding urine in 120 minutes. (author)