A procedure, based on the selective adsorption of radionuclide on glass, has been worked out for the separation of Pa-233 from irradiated thorium and for the removal of Pa-231 target from U-232. The behavior of protactinium towards adsorption from higher concentrated nitric acid solution was examined by using the batch method. Adsorbents used were quartz sand, glass powder and silica gel. Carrier-free Pa-233 has been successfully prepared from irradiated thorium in 10M HNO3solution by adsorption on column containing glass powder, followed by the elution with s M HCl-0.015M HF solution. By means of the similar procedure, U-232 produced by irradiation of Pa-231 has been obtained effectively from the highly α-radioactive target materials.
It was found by chance that a pharmaceutical radio-rose bengal (131I-RB) was remarkably decomposed when it was heated with a commercial infrared lamp. Assuming that the heat and light would mainly affect this phenomenon, the effects of the heating at 100° or 123°C for 0.5 hrs. and of the illumination under a fluorescent lamp for 7 hrs. were examined, and it was found that in the former the activity of the Rf0.85 spot in the paper chromatography increased about a half compairing with that of the sample illuminated with the infrared lamp, and in the latter there was no change. It was evident from the data by the paper and thin layer chromatography, and the quantitative analysis of iodine that the main component of this spot was consisted with the radioactive iodide itself.Consequently, this decomposition seemed not to depend upon the chemical change but on the radiochemical one, i.e., specific release of131I by the long wave light and the heat of the infrared lamp. So, we claim that in order to prevent the radiochemical decomposition mentioned above, the131I-RB has to be prepared, stored and treated carefully. It was observed that the commercial131I-RB contained the radioactive impurities as much as over 10% because the131I-iodide of about 6.5% and another impurity which was already known (probably triiodo-TCF) of 5% or so were detected.
These experiments were initiated in order to clear the discussion that 2, 2-thiobis-4, 6-dichlorophenol, i. e. Bit hinol (Bitin) has a characteristic effect on the insect for human paragonimiasis. The behavior of bitin in the body of the dog was studied with the aid of radioactive tracer technique. Radioactive bitin was synthesized in the following way. 35SCl2was prepared at first by the reaction between S mixed with35S and 5% Cl2-CCl4using AlCl3as catalyzer. By the reaction between35SCl2and 2, 4-dichlorophenol using the same catalyzer, bitin-35S was obtained. The powder of radioactive bitin was orally administered to dogs, which were anatomized 24 and 48 hrs. later. Radioactive matter was washed out of the organs of the dog using acetone as a solvent. After evaporating the solvent, the radioactivities of the residues were measured. On the basis of these data it was found that a large part of bitin was discharged out of the body as exprements and a small part of bitin, however, was observed in urine, liver, lungs, kidneys and pancreas 24 or 48 hrs. after ingestion. In the other organs a very small part of bitin was observed. In view of the existence of bitin in lungs, it is assumed that bitin has a characteristic effect on the insect for human paragonimisic. On the other hand, as compared the absorption spectra of bitin ethanol solution which was exposed in sunlight for a long hrs. with that of ethanol solution of the urine of the dog, it seemed reasonable to assume that bitin was oxidized in the body of the dog.
Although assessment of the spatial characteristic (isoresponse curve) of scintiscanner collimator is important, it requires timeconsuming boresome labor, especially in determining the response in water. Tsuyascan can not be applied in assessment of a heavily shielded scintillation detector due to its limited flexibility of demounting from the scan deriving mechanism. A line phantom makes the assessment of collimator very simple and fast procedure. The line phantom is the concept denoting that a straight tube containing a homogenous radioisotope solution is placed diagonally (45° against the horizon) in a water bath, either filled with water or not (air) . As for the inside diameter of the tube, the smaller the better. The assessment procedure of the collimator for a certain radionuclide is just rectilinearly scanning over the line phantom containing the radionuclide.