Accumulation of137Cs in trefoil (leaf and stem), “Mitsuba”, Cryptotaenia japonica Hassk, with or without root was investigated to prepare higher radioactive plant in hydroponic culture medium (140-150 Bq/ml) . It was found that137Cs concentration in plant tissue was increased with time, as high as 1.6 times of that in the culture medium after 4 days. On the other hand, 137Cs concentration was affected by carrier element (Cs > 6ppm) and coexistent elements in the medium. Radioactivity of the plant after 4 days was shown to be sufficient for successive experiments.
The comparative study of the blood clearance tests of99mTc-Phytate (99mTc-P) and indocyanine green (ICG) was undertaken in liver-injured dogs with D-galactosamine (GaIN) . The blood clearances of99mTc-P and ICG in dogs decreased with the increase in dose of GalN and with the time elapsed after GalN administration. As compared with the blood clearance test of ICG, the blood clearance test of99mTc-P in dogs was found to be more sensitive in detection of the hepatic dysfunction with mildly damaged stage, but to be relatively inaccurate in detection of the hepatic dysfunction with severely damaged stage induced by GaIN.
A NaI-NaI coincidence low background counting system has been constructed to be used in radioenvironmental measurements. The slow timing technique, using the constant fraction timing single channel analyzer and coincidence unit, was used in the present system. The coincidence efficiencies of systems employing two and four NaI (Tl) detectors have been evaluated. A scintillation preamplifier with multiple inputs was constructed for summing the outputs of PM tubes. The performance of the system was tested using radioactive point sources and environmental samples. The detection efficiency of the NaI-NaI coincidence system employing four NaI (Tl) detectors was found to be high enough to measure low-level γ-ray activity of desired isotope in environmental samples with neither high background contribution nor interferences from other isotopes.