A new observation method of colored luminescence or after-glow (phosphorescence), emitted from rock slices immediately after γ-ray irradiation, has been developed using a normal color-film. The film was directly faced to the irradiated slices for a relatively short period like 2-5 min in a black bag. According to this simple procedure, the resultant photographs showed unexpectedly colorful images depending on the mineral constituents in slices. The intensities of the after-glow color images (referred to as AGCI) were found to be dependent on the dose rates rather than total doses. In the AGCI, the apparent variations of emission intensity were observed even within individual minerals as well as color changes affected by thermal metamorphism. A qualitative decay behavior has been clearly seen in the successive AGCI results. The proposed conventional AGCI technique is considered to become a promising tool applicable to varieties of mineralogical investigations as well as the additional information concerning the intrinsic physical properties of other solid materials.
In about 20 specimens of untreated human soft tissues, Th and U, were analyzed by ICP-MS. The concentration values obtained, particularly in the case of U, tended to be lower than reported ones. In order to investigate the source of the discrepancy, human tissue samples (treated for preservation), which had been analyzed for U in the previous study by fission tracks, were analyzed again by ICP-MS. This demonstrated the difference may be a reflection of the variance between treated and untreated samples. The problems involved in the analysis and the sample treatment are discussed.
Comparison of myocardial imaging with simultaneous administration of201TlCl and123I-MIBG are examined. However, as there are both cross talks on to201Tl-photopeak window from123I and to123I-photopeak window from201Tl, it is important that we understand these quantitative cross talks, previously. The purpose of this study is to estimate the relative cross talk on to each photopeak window from another nuclide. These cross talks determined from gamma rays spectra, which were measured by inputting signals from a gamma camera into a multi-channel (2048 ch.) pulse height analyser. Three types of collimators, which are HR (high resolution), AP (all purpose) for low energy, and ME (medium energy), and cuboid phantoms (size of the base: 10×10 cm2) were used in this experiment. As a result of the cross talk measurement, uses of the HR- and the AP-collimator were not suitable for myocardial imaging with123I-MIBG, because123I emits mostly gamma rays with energy of 159 keV and some gamma rays of higher energies, moreover, the lead characteristic X-rays contribute considerably on to201Tl-photopeak window. When the phantom containing both nuclides of201Tl and123I with equal activities was imaged with the gamma camera, the cross talk fractions to the201Tl-photopeak window were 45-50% for the HR-, 34-40% for the AR-, and 9-10% for ME-collimator. Also, those to the123I-photopeak window were 9-12%, 9-12%, and 7-11% for the HR-, the AP-, and the ME-collimator, respectively. From the above results, we recommend the use of the ME-collimator for myocardial imaging with simultaneous administration of201Tl and123I.
Sorption of two alpha nuclides, 237Np and239Pu, on granite was studied by the autoradiographic method using a solid state track detector (CR-39) . The autoradiographs for the surface of rock thin sections of the Inada biotite-granite which were immersed for 48 h in the ground-water containing both nuclides, showed that the alpha nuclides sorbed preferentially on biotite rather than on quartz and feldspar. Mechanism of the alpha nuclides sorption on granite was discussed based on the results of optical microscopic observations of the thin section, track density measurements and alpha-ray spectrometry. It was considered that the ion exchange seems to be a major mechanism of the sorption of these nuclides on the granite.
Chitosan derived from chitin which is a cellulose-like biopolymer distributed widely in nature, especially in shellfish, insects, fungi and yeast, is known to be one of the natural chelating agents. The purpose of the present study is to investigate whether chitosan can be applied to the animal and human body in order to reduce the bioavailability of radiostrontium in foods. Chitosan solution was orally given and immediately after then85SrCl2was administered to rats using a stomach tube. The whole-body retention of85Sr determined by in vivo counting was lower than that of control rats which were not given chitosan. The activity ratio in urine and f eces f or chitosan-treated rats was higher than control rats. Ten percent of alginate food was given to rats during 10 days and85Sr was administered orally. The whole-body retention of85Sr alginatetreated rats was decreased sharply compared with control rats. These results suggested that chitosan and alginate can be used as a drug to reduce bioavailability from gastrointestine of ingested radio strontium.
An anticoincidence shielding has been developed for a low-background well-type Ge detector. The detector in a heavy lead shielding was surrounded by plastic scintillators to reduce background produced by cosmic rays. Background counting rate in the energy range 40 keV to 3 MeV was reduced to 1/2.2 at anticoincidence mode. An example of low-level γ spectrometry utilizing this detector assembly is given.
We measured serum and urinary concentrations of type IV collagen by radioimmunoassay (RIA) in patients with renal diseases and compared them with normal levels. In diabetics with macroproteinuria or with renal insufficiency, serum and urinary concentrations of type IV collagen were higher than in diabetics without nephropathy or with early renal damage as determined by the presence of microproteinuria. Serum concentrations of type IV collagen in patients with membranous nephropathy (MN) showed a significant increase compared with normal controls. Urinary concentrations of type IV collagen in patients with MN, minimal change nephrotic syndrome at the remission phase and nephrotic phase and IgA nephropathy showed a significant increase compared with normal controls. These increases may indicate that a change in basement membrane metabolism has occurred in these renal diseases.