In order to detect a radioactive band on the paper strip developed by focusing chromatography, plate-making-film was used for the autoradiography and β-spots were photographed. Thereafter the film was etched with sodium hydroxide solution to find the a-tracks. Paper strip used for the sample was prepared by the precipitation focusing chromatography of226Ra and its daughter nuclides using HCl-KF solution as a developer. The film used was not high in its β-sensitivity, but because of its high resolution good photographic results were obtained according to the intensity of β-activity when the proper conditions of photographic development were fulfiled. The simple α-spectrometry was made possible by counting the numbers of tracks according to the ething depth of the film. The film was hard and thick enough for etching with 6M sodium hydroxide solution at 50°C for more than 50 hrs to measure the depth of tracks.
When85Kr gas is used as an internal radiation source for chemical reactions in liquid phase, it is necessary to check after irradiation whether the radioactive concentration of85Kr dissolved in the solution is below permissible level or not. Measurements were made on solutions ranging in concentration from 1×10-3-1× 100kBq/g (1×10-4to 1×10-1μCi/g) by the use of an end-window GM counter for β-rays. In the present paper, the method of making up the calibration curve for85Kr solution is studied, together with some problems in measurement. The calibration curve for85Kr solution was represented as N=1.8×105C. In addition, the method for measuring concentration of dissolved85Kr was established by resolving problems relating to the volatilization of85Kr in measurement.
Techniques for the production of three kinds of192Ir sources, i.e. hairpin, single-pin and seed, for brachytherapy were developed in Japan Atomic Energy Research Institute. Platinum-iridium alloy wire sheathed with platinum tube in advance were irradiated by the JRR-2 or JRR-3 reactor. The platinum tube cuts of beta-rays so as to minimize unnecessary radiation exposure to patients. Irradiation conditions were determined to obtain the radioactivity of 0.74 GBq (20 mCi) for a hairpin, 0.37 GBq (10 mCi) for a single-pin and 0.37×10-1GBq (1 mCi) for a seed, respectively, at the end of irradiation. Fluctuation in the linear distribution of the radioactivity along the hairpin source or the single-pin source was small enough on the viewpoint of its application. No significant impurity or surface contamination was observed in the source produced with pre-encapsulation. Seed targets were loaded in a polyethylene tube so as to be suitable for the new treatment technique of tumor. Irradiation of seed targets, packed alternately with nylon spacers in a polyethylene tube, was found to be satisfactory for preparing ribbon sources.
Serum digoxin concentrations measured by stat RIA (phadebas digoxin RIA kit) correlated well with results obtained by complete assays. The result of stat assay can be reported within 1 hour, measuring one or more samples together with 2 standard samples in duplicates. Precise measurement can be expected with serum digoxin concentration over 0.5 ng/ml. The stat assay allows to apply the theory of pharmacokinetics for the estimation of digoxin concentration at steady states measuring minimum digoxin concentration (Cn (min) ) on the 3rd to 6th day after the start of digoxin therapy. The estimated serum digoxin levels were well agreed with measured values with the difference ranging from Y.6 to 8.6% in CV. The method is usefull for the planning and assessment of appropriate digoxin regimen.