During 1962 to 1969, in the drainage area of River Edo, River Agano and River Yodo, annual variation of removal of90Sr from fall-out into the river was analyzed in various discharge processes from hydrometeorological and radioecological situation. Namely, following equation was obtained from annual amount of discharged90Sr into river Q (sr) (Ci), annual precipitated fall-out90Sr R (Ci), annual rain fall r (m) and it's run off coefficient Cr and deposited90Sr in surface soil (depth; 0-5 cm) in end of the previous year d (Ci), total deposited90Sr in soil D (Ci) in the drainage area, and C1, C2 and C3, which were coefficients related to discharge processes of90Sr. Q (Sr) =C1⋅R⋅Cr+C2⋅ (R+d) ⋅γ⋅Cr+C3⋅ [D- (R+d) ] ⋅γ⋅Cr Each C1, coefficient related to“channel precipitation”of90Sr, was negligible in the Edo River basin, 0.00626 in the Agano River basin and 0.0748 in the Yodo River basin, each C2, coefficient related to “surface run off+a part of interflow”of 90Sr, was 0.0110, 0.0187 and 0.0171, and each C3, coefficient related to“the other part of interflow+ground water flow”of 90Sr, was 0.00552, 0.00585 and 0.0104 respectively. In order to observe the patterns of annual discharged amounts in various discharge processes, hydro graphical analysis was carried out and the same tendency was observed in the three river basins. The peak year of“channel precipitation”indicated the same peak year of R, and the peak of“surface run off+a part of interflow”delayed 1-2 years and that of“the other part of interflow+ground water flow”delayed 5-6 years after the peak of R. Each Q (sr) was 0.7-2 Ci in River Edo, 5-14 Ci in River Agano and 3-10 Ci in River Yodo, and each discharge rate of90Srfrom soil in each drainage area into the river ( [Q (Sr) -C1⋅R⋅Cr] /D) was 0.2-0.4%, 1-2% and 1-2% respectively.
In order to investigate the tumor affinity radioisotopes, vanadium (V-48), niobium (Nb-95), tantalum (Ta-182), arsenic (As-74) and antimony (Sb-124) —the elements of group V in the periodic table—were examined, using the rats which were subcutaneously transplanted with Yoshida sarcoma. Six preparations, 48VO2Cl, 95Nb-oxalate, 182Ta-oxalate, Na2H74AsO4 (Na2HAsO40.008μg), Na2HAsO4 (Na2HAsO41 mg) and124Sb-chloride were injected intravenously to each group of tumor bearing rats. These rats were sacrificed at various periods after injection of each preparation: 3 hours, 24 hours and 48 hours in all preparations. The radioactivities of the tumor, blood, muscle, liver, kidney and spleen were measured by a well-type scintillation counter, and retention values in every tissue including the tumor were calculated (in percent of administered dose per g-tissue weight) . 95Nb-oxalate had considerably strong affinity for the malignant tumor.48VO2Cl, 182Ta-oxalate, Na2H74AsO4and124Sb-chloride did not have any affinity for the malignant tumor. But48VO2Cl had fairly strong affinity for the kidney, Na2H74AsO4had very strong affinity for blood-corpuscles and strong affinity for the spleen.182Ta-oxalate and124Sb-chloride did not have any affinity for the organs and182Ta-oxalate was slowly excreted and124Sb-chloride was rapidly excreted in urine.
Electron microscopic autoradio grams demonstrated that the cytoplasmic67Ga is mainly associated with the cell membrane and the mitochondria. Intracellularly the mitochondrial and microsomal fractions contained 34.8 % and 20.5 % of the activity respectively. In vitro, Ehrlich's tumor cells with either cell membranes damaged by EDTA or altered chemical function by an anticancer agent showed a significant decrease in67Ga uptake.
There is no report of using of radioactive tin for skeletal imaging. As previously reported, 113Sn-citrate had very strong affinity for bone. Among the isotopes of tin, 117mSn had ideal physical characteristics for gamma camera systems. In order to evaluate possibilities of bone scanning with117mSn, the present study was performed. Before embarking on the production of117mSn, we decided to use113Sn in a series of experiments with rats. Localization of bone-seeking compounds in the skeleton differs considerably with the age of animals. Consequently, 85Sr (as chloride) was used with113Sn-citrate in these experiments as a biological standard.113Sn-citrate and85Sr-chloride were injected intravenously to each animal, respectively. The animals were sacrificed serially from 1 to 24 hours after injection. The soft tissue (except kidney) and blood concentrations of113Sn-citrate were less than those for85Sr at 1 hour and 3 hours after injection, and were similar to those for85Sr at 24 hours after injection, whereas the skeletal concentration of113Sn-citrate were slightly less than those for85Sr from 1 to 24 hours after injection. The cumulative urinary excretion of113Sn at 3 hours was approximately 54% (compared with 3% of85Sr), the residue, which was almost accumulated in bone, was excreted very slowly in biological half-life of 31.5 days.113Sn-citrate had excellent biological property for bone scanning agent, compared with85Sr. It is the major advantage that113Sn-citrate was excreted in urine and was hardly excreted in the gastro-intestinal tract.