An experimental apparatus for enrichment of85Kr, which consists of 8 metallic separation columns with hot wire, was designed and constructed for the development of enrichment technique of85Kr by thermal diffusion method. Total effective length of the column is 18.4m and maximum amount of85Kr treated is 200 Ci. The method for measuring temperature of the hot wire and the optimal material used for the hot wire were investigated prior to design this apparatus. It was possible to measure the temperature of the hot wire with fairly good precision by specific resistance method. Of 8 kinds of metallic wires, tungsten wire was chosen as an optimal hot wire, by taking into consideration of 7 terms for the selection of the hot wire.
Axial radioactivity distributions in 60Co source pencils were measured with a lead collimator and a cavity ionization chamber. Axial γ-ray intensity distributions in the irradiation canister sorrounded by the pencils were measured with a dosimeter consisting of a silicon diode and a charge integrator. The latter distributions well agreed with those calculated from the former distributions by assuming the linear source model. The optimum radioactivity distributions for some arrangement diameters were searched from a point of view of the homogeneity in γ-ray intensity.
Testing performance of the improved pinhole collimator of 1.5 mm aperture attached to the gamma camera was carried out with three kinds of radionuclides, 99mTc, 67Gaand131I, using a hand-made phantom. The results obtained in this experiment were compared to those obtained with a human pinhole collimator of 4 mm aperture. Those were nearly understood by taking account of the effective aperture of a pinhole collimator for each effective photon energy. And all scintigrams obtained from rats with various scintigraphy showed high resolution images.
From the clinical use of RIA-gnost trypsin kit, the following results were obtained. 1. Standard curve showed a steep and good curve was shown. 2. Incubation: The condition for the first incubation was set at the room temperature for 10-24 hours and that for the second incubation at the room temperature for 3-5 hours. With these settings, satisfactory results were obtained. 3. Reproducibility and recovery: The C.V. of the reproducibility and the recovery were considered superior, and the values were below 10% and ± 3 %, respectively. 4. Correlation between trypsin and serum elestase-1: An excellent positive correlation (coefficient of correlation r=0.889) was shown. 5. Serum trypsin concentration of normal and pancreatic diseases: The normal range was from 100 to 500 ng/ml. Acute pancreatitis rose obviously. Diabetes mellitus and chronic pancreatitis was below 500 ng/ml and the pancreatic cancer showed a tendency to scatter in the range of 50-1250 ng/ml. The above results indicated that serum trypsin can be easily measured with high precision by using this method. Thus the method is considered useful for the diagnosis of pancreatic diseases.
Gamma ray waste water radiation monitor has been improved by using multichannel analyzer. Maximum permissible concentrations of125Iare one thousandth lower than51Cr.This condition, the radioactive waste water cannot be pumped out occasionally. Gamma ray energy spectrum is measured by microcomputer based multichannel analyzer by which125Iphoto-peak counts is separated from other radionuclide counts. Also detecting vessel is washed with pressured fresh water to prevent contamination.