A fully automated apparatus for repeated production of13NH3from proton-bombarded water has been developed. Its operation sequence consists of the introduction of NaOH, the bombarded water containing13NO3-and TiCl3into a reaction vessel, the distillation of13NH3formed by the reduction of the13NH3-, and the washing of the vessel for the next sequence. The NaOH and TiCl3are added as 4ml of saturated solution and 4ml of 10% aqueous solution, respectively, and halogen lamps are used as the heat source for the distillation. By this apparatus, 13NH3can be produced automatically and repeatedly in a radiochemical yield of 80-90% within 10 min from the EOB.
In an attempt to study the availability and limitation of analytical data of human hair as an indicator of environmental pollution and/or of human health effect, concentrations of elements in 202 scalp hair samples collected from local population in the Tokyo Metropolitan area were determined by instrumental neutron activation analysis. The correlation coefficients between concentrations of 13 elements in each sex and in each age group were calculated and discussed. There were significant correlations between some pairs of elements, i.e. Na-K, Br-Cl, Ca-Zn and Ca-Mg, in all five age classes in both of male and female, indicating that the correlations were consistent. Ca was observed to be reversely correlated with Cl. No significant correlation was apparent between Hg and Se, when the correlation coefficient was calculated using logarithmic converted concentration data.
Radionuclide Computed Tomography (RCT) was studied from the technical standpoint of view. In this study, a gamma camera (Ohio Nuclear Σ410S) and a rotating chair designed by one of us were used. The computer used was Scintipac 1200 (32 kW memories and 2.4 MB×2 disk memories) . A cylindrical phantom having a diameter of 20cm was also designed by us into which various-sized tubes could be inserted for resolution study. The phantom was set on the chair, the center of which was 20cm of from the surface of the detector. The chair was rotated manually 10 degrees, and finally 36 digital images in the form of 64×64 elements were obtained, covering an entire circumference. RCT images were displayed in the form of 128×128 elements on a X-ray film through a Microdot Imager. At first, the phantom was filled with99mTc solution and the uniformity of the RCT image on it was checked using several formulae for count rate correction to find out which one of the formulae was best fitted. For the reconstruction of the RCT image, “filtered back projection”was used. Then, we found that, as far as our phantom study was concerned, simple geomet-rical mean on the data from the two opposing directions was found the best for the count rate corrections, which was exclusively used thereafter. The fluctuation on the uniform source was found to be approximately 15%. For the resolution study, hot tubes having diameters of 1.0, 2.0, 3.0, and 4.0 cm and cold tubes of 1.5, 2.4, 3.5, and 4.7cm were inserted into the phantom. As for the hot tubes, all the tubes were depicted on the RCT image whereas 2.4cm was the smallest depicted for the cold tubes. FWHM was checked with a fine line source in the phantom and was found to be 2.0cm regardless of its depth. The Alderson liver phantom was also used to detect defects in the air and it was found both balls having diameters of 2.7 and 3.7cm could be depicted on the RCT image. Now we are evaluating clinical usefulness of this technique on the liver. The results will be published in the near future.
The system consists of a conventional RIA total system with a desk-top computer system, and a filing and reporting system of the RIA data with a flexible disk and a printer. Patient's identification is registered in the computer at the time of reception to RIA test. Their identifications are, reception date, name of RIA test, patient name, age, sex, doctor's name, name of clinical department, in-or out-patient, number of samples and it's sampling time, examination date of assay and comments included normal value. These data are recorded to a flexible disk sheet, and are combined with RIA examination data, when data process of radioimmunoassay finished. Result of the RIA test is automatically printed by the printer. Printed parameters are results of examination with standard deviation, and above descrived patient identifications. If necessary, time activity curves of the density are plotted too. Accurate and automatically reporting system has been applied to the routine RIA test.