The electrolysis method was applied to the labeling of tetracycline and oxytetracycline with99mTC. The product may be expected as a tumor localizing agent or a kidney scanning agent. The labeling efficiency depends on the pH of electrolytic solution and the quantity of electricity. Under the optimum condition, the labeling efficiency was found to be 90-95% by the use of Sn-Pt electrodes. The labeled products must be used within one hour after the preparation, because they were unstable in aqueous solution and99mTc was released as99mTcO4-in the course of time. The organ distribution was determined by the use of mice and rats with or without Yoshida sarcoma. Rapid clearance from blood and slow excretion from kidney gave a good image of kidney 1-3 hr after the administration in rats. The localization of99mTc-tetracycline and99mTc-oxytetracycline into tumor was not remarkable. The labeled products presented here may be expected as a kidney scanning agent.
Automatic data processing of radioimmunoassay results is now one of the most important parts in the radioimmunoassay laboratories. Especially in handling all batches of samples, it allows us to process radioimmunoassay results with simplicity, rapidity and reproducibility. Recently, some instrumentation appeared which could count and calculate the sample concentration automatically using some type of approximation of the standard curves. Rectangular hyperbola is employed for IRI, a-FP, HGH etc., but approximation of HTSH standard curves using rectangular hyperbola is impossible. Theoretically, linearization of the standard curves of HTSH are possible using logit transformation of bound percent (Y) and log concentration (X) in the case of univalent homogeneous antigen-antibody reaction. However, this is not always true in the routine radioimmunoassays because of several factors associated with the procedure. From these reasons, authors divided the standard curve into two parts at the point of middle concentration (31.2μU/ml) and calculated each linear regression line from logit (Y) and loge (X) of the standard curve (two-divided logit transformation method) . These calculations were made using a small desk-top electronic program calculator (Canola 1614P) . After determination of coefficients of each regression line, sample HTSH values were calculated semiautomatically using newly developed calculation program. In the 113 samples correlation coefficient between two-divided method and usual graphic method was highly significant (γ=0.9977, p<0.001) . To compare this, correlation coefficient between single logit transformation and graphic method was γ=0.9906 (p <0.001), and correlation coefficient of our method slightly improved compare to the single logit transformation. Almost all the standard curves obtained by plotting loge (X) against logit (Y) showed single monophasic curves, and the inflexion point lay near at the middle point of the standard curves. This may be variable according to the change in the composition of the radioimmunoassay kits, but relatively stable at the middle point of the concentration. This may be the reason why our method well correlated with usual graphic method. Our method employes only a small desk-top electronic calculator and simple handling manner, and could be done semiautomatically. And it was found to be useful in clinical bases, even in the small laboratories.
Thirty-one dynamic renoscintiphotographs and renograms, using instantly prepared99mTc-Sn-DTPA (by Daiichi Radioisotope Labs., Ltd.), were obtained from 27 patients with various renal diseases. Simultaneously, 17 of 27 patients underwent renography using sodium iodohippurate (131I), and the results were compared with those of99mTc-Sn-DTPA. The results are summarized as follows: In99mTc-Sn-DTPA, fast and slow dynamic study such as scintiphotographs of vascular phase and functional phase, and renogram, can be performed using only one kind of nuclide. Especially, this nuclide is effective in the diagnosis of renal tumor. The curve of renogram by99mTc-Sn-DTPA is more gentle and tends to have a delayed peak time compared with that by sodium hippurate (131I), on this curve yet the evaluation of renal function can be done satisfactorily. Furthermore its application to regional renogram is considered to be possible. Evaluation of renal function of serious cases is difficult, however. In such a case, evaluation of renal function by the image, which is used to be given through scintillation camera, will become important. Renal studies with99mTc-Sn-DTPA didn't produce any side effects.
In order to investigate the diagnostic possibility of diffuse liver disease by99mTc-Sn-phytate (produced by Daiichi Radioisotope Labs., Ltd.), 99mTc-Sn-colloid (electrolysis, Dainabot Radioisotope Labs., Ltd.), and by99mTc-Sn-colloid (Daiichi Radioisotope Labs., Ltd.), 198Au-colloid and above three kinds of99mTc-compounds were administered respectively to 68 cases including 32 with diffuse liver disease and 36 others, and the scintigrams and KL values obtained therefrom were compared reciprocally. In the examination, the scintigram obtained by99mTc-Sn-phytate closely resembles that by198Au-colloid. Moreover, its KL value was fairly close to that by198Au-colloid. From those facts it was concluded that99mTc-Sn-phytate is useful in the diagnostic evaluation of diffuse liver disease. As for the remaining two kinds of99mTc-Sn-colloid, they were not considered to be ideal for the above evaluation due to their excessively high splenic uptake, and fairly high and variable KL values. They seemed rather to be adequate for the tumor diagnosis or spleen scintigram. When those99mT c-compounds were administered, no remarkable secondary effect was detected. It was therefore concluded that they all were quite safe compounds to be handled.
The apparatus for electrolysis was obtained from Dainabot Radioisotope Laboratory. Three hundred and sixteen cases of various kind of liver disease such as hepatoma, metastatic liver cancer, liver cirrhosis and hepatitis were subjected to study, and 335 examinations were done in 10 months. In all cases, the examinations were successful in demonstrating liver and spleen for the evaluation of size, shape and the existence of filling defects. Bone marrow was also observed in some cases. Apart from such RES organs, the kidneys were observed on the scintiphotos on several examinations. According to the chronological sequence of study, these examinations were divided into 6 groups. In cases of group I, the kidneys appeared in 15 out of 23 cases; while in group II 8 out of 39 cases, however, in none of 18 when we used counter-electrolysis after normal electrolysis; in group III 7 out of 41; in group IV 15 out of 34, including 7 instances of second use of the same vials; in group V only 1 out of 42 and in group VI 7 out of 156. In sum up of V and VI groups, 8 out of 198 (4%) . Paper electrophoretic study indicated that the presence of the technetium compound having plus ion might play some role in the mechanism of renal uptake. This substance was cleared in the course of time, and also by the counter-electrolysis. In conclusion, the preparation of technetium-Sn-colloid by this kind of electrolysis apparatus of these days was found useful for the demonstration of RES organs, if each vial was used once only.