Microautoradiography using conversion electron and Auger electron of the isotopes119mSn and51Cr which were diffused from the surface in pure iron was investigated. The surface layers were removed successively by chemical reagents to prepare the specimens for microautoradiographs. The density of silver particles was measured in the boundary region and was normalized by comparing with the density near the triple point of the grain boundary. Differences of the diffusion coefficients in the grain boundary were investigated from the frequency diagram of the isotope concentrations near the boundary in individual specimens
Silver and cerium in the liver and the kidney from severely burned infant were analyzed by neutron activation method. The patient was treated topically with cerium nitrate/silver sulfadiazine cream and cerium nitrate solution for 3 months. Then, the treatment with these drugs was stopped because of abdominal distention. The patient died 1 month after the cessation of the treatment with these drugs. The tissue specimens, blank liver sample and reference standards were irradiated with TRIGA MARK II Reactor of Rikkyo University. About 1 month after the irradiation, the activities were measured with a Ge (Li) detector coupled to a 4096 channel pulse height analyzer. A large amount of silver was detected both in the liver and in the kidney and a trace of cerium only in the liver. A considerable amount of silver was detected in the liver and its quantity was about 1600 times more than that of normal livers reported by Hamilton, Minski and Cleary (1972-73) . Neither silver nor cerium were detected in the blank liver. These results suggest that prolonged topical chemotherapy of cerium nitrate/silver sulfadiazine cream and cerium nitrate solution for the extensive burn injuries causes considerable absorption of silver and cerium into the liver and the kidney.
Generally, it is reported that the smallest tumor that can be detected with the67Ga scintigram is limited to a diameter of approximately 3.0 cm. To surmount that limitation we have attempted to detect small lung cancer by means of quantitative external counting of67Ga uptake rather than the qualitative scintigram. Seventy-two hours after67Ga injection, the uptake counts of tumor (T) and a corresponding normal region in the opposite lung (N) were measured with scintillation camera. The67Ga uptake ratio ( (T-N) /N) could then be calculated. The67Ga uptake ratio of 6 pulmonary adenocarcinomas was measured to be 0.05-0.22. In contrast, the67Ga uptake ratio of benign lesions such as tuberculoma, pulmonary infarct, cyst, pneumoconiosis, mucoid impaction, hamartoma and chronic inflammatory lesion with calcification resulted in negative values (-0.01--0.77) . From these results, it was possible to differentiated small adenocarcinoma of the lung tumor from these benign diseases. However, the67Ga uptake ratios of 4 cases of active tuberculosis, 5 chronic inflammatory lesions and 1 granuloma were 0.01-0.41. The cases with more than 0.30 of67Ga uptake ratios all represented active inflammatory lesions. However, there were some cases of inflammatory lesions where the values overlapped with adenocarcinoma.