A newly developed apparatus of tritium enrichment by electrolysis, using solid polymer electrolyte, was quantitatively examined. The concentration of enriched standard water was measured by a liquid scintillation counter in order to determine the tritium recovery factor and the apparent tritium separation factor. An average apparent tritium separation factor was βa=5.6. Assuming that the tritium separation factor was constant, the relative standard deviation of tritium recovery was 4%. The apparatus was found to be very useful for environmental tritium enrichment, since it can be operated with easy and safe procedure, as well as the reduction of electrolysis time.
Adsorption equilibrium models were proposed to estimate the distribution coefficients (Kd) of60Co, 85Sr and241Am in the presence of humic acid. The Kdof the three radionuclides for a coastal sand, which does not adsorb humic acid, could be expressed by the adsorption equilibrium model taking account of only the complexation of the radionuclide with humic acid in the aqueous phase. On the other hand, the Kdof the three radionuclides for an ando soil, which adsorbs humic acid very well, could be evaluated by the adsorption equilibrium model taking account of the effects of the adsorption of both humic acid itself and humic complex of the radionuclide on the Kd, besides complexation in aqueous phase.
A simultaneous scan of transmission CT and emission CT using a large field gamma camera was tried to make a fusion image. On a phantom study using133Xe or 201Tl for emission CT source and99mTc for transmission CT source, the fusion image was created without truncation artifact. On a clinical study of brain tumor, the fusion image was successfully obtained.
In general, the sewerage at radioisotope laboratories has very strong stench. We treated the sewerage with a total water treatment agent (Tachileslegi, Nippon Nouyaku Co., Ltd.) that is widely used for prevention of slime, scale, corrosion in cooling towers. As the result, the stench was decreased to about two thirds to that of control estimated by odor-test.