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  • Author or Editor: R. Amano x
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Abstract  

Radioactive implant induced X-ray emission (RIXE) spectrometry was examined by mixing a sample in solution with a radioisotope. The radioisotopes of57Co,67Ga,75Se,99mTc,111In,125I and201Tl were used as implant X-ray excitation sources. Copper, strontium, iodine, barium, lead and uranium solutions were used as samples to be analyzed. K X-ray for all samples and L X-rays for lead and uranium samples were measured with a pure Ge detector. The excitation characteristics of each radioisotope are discussed using the effective excitation efficiency (eff) defined by the equation eff=Nc/(NaNd), where Nc is the number of counts in the X-ray peaks, Na is the number of atoms of interest in the sample, and Nd is the total number of decays of radioisotope for the counting interval.

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Abstract  

Reversed-phase high-performance liquid chromatography with u.v. detection was applied for rapid and sensitive determination of pertechnetate in99Mo/99mTc generator eluates, using a mixture solvent of acetonitrile and 0.04M aqueous acetate buffer (1/1) containing a few volume percentage of 0.5 M tetra-n-butylammonium hydroxide as the mobile phase. Employing a -bondapak C13 column, the TcO 4 species was separated, monitored with absorbance at 254 nm, and observed at the retention time of 3.5 min. The detection limit was found to be 5.2·10–10 g of Tc for each injection. Total Tc contents in the99mTc eluates from clinically-used99Mo/99mTc generator were analyzed by this technique. The99mTc (99Tc) species was separated from the contaminant99Mo. This method was found to be useful for the purification of99mTc (99Tc) as well as the determination of total Tc content.

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Abstract  

Preparation of thin films of lanthanide (Ln) sulfides has been studied by the chemical vapor deposition (CVD) method, using metal -diketonato chelates with 2,2,6,6-tetramethyl-3,5-heptanedione and reactant H2S gas as starting materials. Two kinds of sulfides, Ln2O2S oxysulfides and EuS monosulfide, were obtained as thin films at temperatures as low as 390–570 °C. The CVD method was confirmed to be suited for the above purpose.

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Abstract  

Radioactive multitracer technique was applied to study the brain regional uptake of trace elements by the normal mice during aging. The brain regional radioactivities of 46Sc, 54Mn, 65Zn, 75Se, 83Rb and 88Zr were measured 48 hours after intraperitoneal injection of a solution in normal mice aged 6 to 52 weeks to evaluate the brain regional (corpus striatum, cerebellum, cerebral cortex, hippocampus, and pons and medulla) uptakes. The radioactive distributions of 46Sc, 54Mn and 88Zr tracers were variable and region-specific in the brain, while those of 65Zn, 75Se and 83Rb tracers were comparable among all regions of interest. The brain regional uptakes of all tracers slightly increased with age from 10 to 28 weeks, and then remained constant during aging after 28 weeks. These uptake variations may be involved in the functional degenerative process of the blood-brain barrier during aging.

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Abstract  

Production of115Cd by means of photonuclear reaction and preparation of a115mIn generator, based on the genetic sequence of115Cd115mIn, were studied. The production rates of115Cd by the116Cd(γ, n)115Cd reaction were determined as a function of the maximum bremsstrahlung energies between 35 and 60 MeV. Then the parent,115Cd, was produced by irradiating about 0.15g of CdO with the bremsstrahlung from a 60 MeV-150 μA electron beam. After the parent in the Cd 4 2− form was adsorbed on the Dowex 1x8 resin column, the daughter was eluted with a physiologic saline adjusted to pH 1. The generator was milked over a period of 3 days, during which time about 900 ml of eluent were allowed to flow through the column. Even after the milkings were repeated 15 times with 60 ml of the eluent, no115Cd was found in the115mIn fractions (the detection limit of inactive cadmium: 0.02 μg).

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Abstract  

Preparation of thin film deposits of lanthanide, thorium and uranium oxides has been studied by chemical vapor deposition (CVD) method using -diketonate metal chelates with 2,2,6,6-tetramethyl-3,5-heptanedione and some reactant gases as starting materials. The deposition process was carried out using a special apparatus designed for the CVD method at atmospheric pressure and temperatures as low as 400–600°C.As a result, it was demonstrated that each chelate used was well suited for the above purpose by its high volatility and reactivity with the reactant, especially with water vapor.

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Abstract  

Preparation of lanthanide fluoride and chloride films has been studied by chemical vapor deposition (CVD) using Ln(thd)3 (Ln=lanthanide(III); thd=2,2,6,6-tetramethyl-3,5-heptanedionato ligand) and Y(thd)3 with gas mixture systems of CF2Cl2 (difluorodichloromethane)/O2 and CF2Cl2/H2. Two kinds of fluorides, LnOF oxyfluoride and LnF3 triffluoride, were obtained separately along a CVD tube at atmospheric pressure and temperature as low as 300–600°C by the reaction of Ln(thd)3 chelates with CF2Cl2/O2 gas system. The chemical characteristics of the CVD products were considered from the thermochemical point of view.

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Abstract  

A radioactive implant induced X-ray emission (RIXE) technique was examined for the in vivo determination of heavy elements. By the use of67Ga,99mTc,123I,123Xe and201Tl implant excitation sources, the excitation efficiency and X-ray attenuation were measured to reveal the potential pairs of source-heavy element of interest for in vivo elemental analysis by the RIXE technique. Detection limits for the RIXE in vivo analysis were evaluated according to Currie's criterion. Four pairs,99mTc–Pb,201Tl–I,133Xe–Cd and123I–Cd are potential.

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Abstract  

The radioactive multitracer technique was applied to a study on the uptake of trace elements in normal C57BL/6N mice. Comparative uptake behavior of46Sc,54Mn,59Fe,58Co,65Se,83Rb and88Zr tracers was examined among 11 organs (brain, cardiac muscle, lung, liver, spleen, pancreas, kidneys, bone, muscle, eyeballs and testes) and blood, and evaluated in terms of the “tissue uptake rate (the radioactivity percentage of injected dose per gram of tissue, %dose/g)”. The multitracer technique revealed reliable data demonstrating characteristic uptake of the 8 trace elements, Sc, Mn, Fe, Co, Zn, Se, Rb and Zr by the brain and other organs, as well as the distinctive features of the accumulation and retention of each element in the brain.

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Abstract  

Radioactive multitracer technique was applied to study the screening of in vivo interrelations between radioactive tracers (46Sc, 59Fe, 58Co, 65Zn, 75Se, 83Rb, 85Sr and 88Zr) and stable Mn species. Comparative uptake rates were examined in the blood, 9 organs (thymus, lung, cardiac muscle, spleen, pancreas, kidney, liver, testes and bone) and 8 brain regions (cerebral cortex, striatum, hippocampus, thalamus and hypothalamus, midbrain, cerebellum, pons and medulla, olfactory bulb) using the 3-weeks-old mice fed the Mn-deficient, -adequate or -excessive diets with Mn concentration from 0.4 to 300.4 ppm. Significant diet-related differences were found for 65Zn uptake in some organs. The dietary Mn-deficient state induced increase Zn absorption in thymus and lung in short-time span (during 48 hours after injection). On the other hand, no significant diet-related differences were observed in any brain regional uptake rates except for 54Mn uptake rate. The screening results are expected to give us new findings concerning the diet-related element-element interrelations in living bodies.

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