Recently much attention is being paid to positron annihilation radiation energy spectrum measurement as a simple method that gives information about the momentum distribution of an annihilating pair. However, this method has a disadvantage that it is sensitive to drifts of the measuring system and the resolution is still insufficient. We have succeeded to reduce the influence of the drifts to a negligibly small degree by using, in addition to the necessary procedure for a temperature control and stabilizing of AC power lines, a compensation technique in data analysis. We have further attempted to improve the resolution by deconvolution processing. By these procedures, we have been able to separate a narrow component which has not otherwise been resolved directly from the spectrum. The resolution attained by this way is 0.43 keV (FWHM), and is two-or three-fold superior to those ever reported.
123I for use in clinical diagnostic procedures has been produced by bombarding antimony with 40 MeV3He particles. The purity of123I was measured with a Ge (Li) spectrometer and a low energy Ge (Li) detector. The123I-product was followed for 1.5 months with a well-type NaI scintillation counter to establish the half-life and confirm the identity of the nuclides. In order to minimize the yield of121I the optimum cooling time and chemical procedures are presented. After 20h cooling, the121I, 124I and125I contaminants were about 1.8, 4.3 and 0.04% respectively. These values were in agreement with those calculated from the thick-target yield curves. The calculated absorbed dose to the thyroid by the123I and by-product nuclides were only 4.3 and 7.3% of131I. 123I could be measured at the window of99mTc of a NaI scintillation camera and a curie-meter with an error of 10%.
Absorption, distribution, excretion and metabolism of SC-11800EE, a combined steroid preparation consisting of SC-11800 (ethynodiol diacetate) as gestagen and ethinyl estradiol (EE) as estrogen in 20: 1 (w: w), were studied with the use of14C-SC-11800 and3H-EE by radiometry in female rats and by the whole body autoradiography in female normal and pregnant mice. The gestagen orally given with EE was rapidly absorbed from digestive tracts and distributed in tissues in various levels. Gestagen levels in liver and kidney exceeded that in plasma. About 75% of dosed radioactivity was excreted in feces largely via bile and more than 20% in urine within 72 hr after administration. The gestagen was metabolized extensively to more polar products and their conjugates. The pharmacokinetic behavior of the gestagen given with EE did not alter after repeated administrations for 7 days, but was slightly different from that without EE, possibly due to the estrogen effect. The pharmacokinetic behavior o f the estrogen was independent from the gestagen given simultaneously. The distribution of the gestagen given with EE revealed by the whole body autoradiography in normal mice were essentially consistent with the radiometric results in rats and that in the pregnant mice showed that the gestagen in fetus was virtually nil under the present conditions.
Diurnal variation of blood sugar, C-peptide immunoreactivity (CPR), free insulin and total insulin were measured in 10 insulin requiring diabetics after obtaining adequate control of diabetes with commercial lente insulin treatment. Following these tests, insulin treatment were changed to monocomponent insulin (MG-insulin) from commercial lente insulin treatment in all subjects and the same tests were performed at 7th day of MG-insulin treatment. Diurnal variations of blood sugar in both groups were not changed significantly. Also changes in CPR of both groups were nearly same magnitude and endogenous insulin secretion in these insulin treated diabetics were suggested except a case of juvenile diabetic subject. However personal variation were great in diabetics with high antibody titer, diurnal variations of total extractable insulin in both groups were quite comparable. And mean diurnal changes in free insulin were resemble to that of CPR. All of these data suggested that clinical effects of MC-insulin and commercial insulin treatment on insulin requiring diabetics were comparable except insulin antibody or proinsulinspeci fic antibody production.
Biologic distribution of99mTc-labeled concanavaline A, lectin with cell-agglutination, in Ehrlich's tumor-bearing mice has been studied to get a promising indicator for the positive delineation of solid malignant tumors. The preparation of 99mTc-Con A was made by two procedure, by Bio Gel P-10 100-200 mesh (0.9×25 cm column) gel chromatography in 0.9% NaCl eluant (procedure A) and only by 0.20 μm membrane filtration (procedure B) . The reducing agent for99mTc-pertechnetate was used with freshly prepared stannous chloride. Labeling yields of99mTc-Con A by Bio Gel P-10 was 60% within void volume and 20% within chelating fractions. 99mTc-labeled substance eluted within chelating fraction was developed to Rf=0.66 by silica gel plate chromatography in 0.9% NaCl solvent and the ninhydrin reaction for it was negative. Though a higher uptake to the implanted solid tumor tissue in mice was found in99mTc-Con A prepared by procedure B than prepared by procedure A, biologic distribution of99mTc-Con A by both procedures were not different, except the liver and high uptakes for liver, kidney and lung were found. Therefore, if99mTc-labeled tumor seeking radiopharmaceuticals would be needed to a high absolute tumor concentration as well as to a fast blood disappearance with a low uptake for different organs as preferable biologic characteristics, 99mTc-Con A might not be expected merely to be used as a useful99mTc-labeled tumor localizing radiopharmaceuticals in clinics.
Subcellular distribution of169Yb and111In was quantitatively determined to evaluate the role of lysosome in accumulation of169Yb and111In in malignant tumor tissue and liver. The following animals and transplanted tumors were used: rats implanted with Yoshida sarcoma and hepatoma AH109A; mice implanted with Ehrlich tumor. 169Yb-citrate and111In-citrate were injected to the rats intravenously and to the mice intraperi-toneally. Ten minutes to 48 hours after the administration of169Yb-citrate and111In-citrate, the animals were sacrificed, and the tumor tissues and liver were excised. Subcellular fractionation of tumor tissues and livers were carried cut according to the method of Hogeboom and Schneider. 169Yb and111In of each fraction was counted by a well type scintillation counter, and protein of each fraction was measured according to Lowry's method. In Yoshida sarcoma and Ehrlich tumor, most of the radioactivity was localized in the supernatant fraction, and small amount of radioactivity was accumulated in the mitochondrial fraction (lysosome contains in this fraction) . But in the liver, most of the radioactivity was concentrated in the mitochondrial fraction and the radioactivity of this fraction was increased with the passage of time after administration. Twenty-four hours later, about 50% of total radioactivity was accumulated in this fraction. In the case of hepatoma AH109A, . radioactivity of mitochondrial fraction was increased. with time after administration, and about 30% of total radioactivity was concentrated in this fraction 24 hours after administration. From these results it is concluded that lysosome does not play an important role in the tumor concentration of169Yb and111In and lysosome plays an important role in the liver, cancentration of169Yb and111In. In the case of hepatoma AH109A it is presumed that lysosome plays cosiderably important role in the tumor concentration of169Yb and111In, as hepatoma AH109A remains some nature of liver.