International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes最新文献

Iodopentamidine isethionate was heated for 70 min with [I-123]- or [I-125]-sodium iodide and ammonium sulphate in the absence of solvent at 140°C. The product, [I-123]- or [I-125]-iodopentamidine isethionate, was purified by ion exchange chromatography. It was stable at room temperature in aqueous solution over several days, in human blood in vitro for at least 24 h (showing no binding to either cells or proteins), in urine over at least 15 h, and during nebulization in both ultrasonic and jet nebulizers.

Adsorption of Zn(II) on clay minerals (kaolinite, montmorillonite and bentonite) has been investigated spectrophotometrically and radiometrically. Both techniques offered fairly consistent results in spite that different procedure was used to obtain adsorbed amount of Zn(II). Adsorption isotherms fit Freundlich type equation depending on pH value of each clay suspension. The adsorbed amount of Zn(II) increased with increasing pH value of the suspension. Remarkable effect of Mg(II) on Zn(II) adsorption was observed in the case of bentonite. The results obtained may be explained by considering different surface properties of individual clay minerals.

A rapid and precise method for the measurement of the mass of 16α[¹⁸F]fluoro-estra-1,3,5(10)-triene-3,17β-diol by GC—MS is reported. The advantages of this technique over others more widely used are discussed.

La complexation du coeur ^99mTcO³⁺ par le 2,10-diméthyl-4,8-dithiaundécane-2,10-dithiol 1 a été réalisée en utilisant un sel d'étain comme réducteur et a conduit à la formation d'une espèce I stable et neutre. Avec le 5-butyl-3,7-dithianonane-1,9-dithiol 2, la même réaction conduit à la formation d'un complexe II instable difficile à isoler. Les études biologiques sur la souris Swiss ont montré que seul I était intéressant (fixation myocardique supérieure à celle du RP 30). Dans le cas des complexes à coeur TcN, on obtient chaque fois deux espèces neutres, soit à partir de [^99mTcNCl₄]⁻, soit à partir de ^99mTcNCl₂[P(CH₂CH₂CN)₃]₂; il est possible, selon les conditions opératoires, de favoriser la formation de l'une ou l'autre espèce et de les isoler par purification. Les résultats biologiques se sont avérés assez décevants.

Tropapride, (exo)-2,3-dimethoxy-N-[8-(phenylmethyl)-8-azabicyclo[3.2.1]oct-3-yl]benzamide hydrochloride, has been labeled with fluorine-18 at the 2- and 4-positions of its benzylic group. Two synthetic pathways were investigated: the first one required the alkylation of the norbenzyl precursor with 2- or 4-[¹⁸F]fluorobenzyl bromide (radiochemical yield of 5% EOB, 180 min); the second method consisted of a reductive amination of norbenzyl tropapride with 2- or 4-[¹⁸F]fluorobenzaldehyde (20% EOB, 110 min). In both cases, the specific activity was found to be greater than 1 Ci/μmol (EOS). Animal studies in rats showed the percentage of the injected dose localizing in the whole brain to be 0.6 ± 0.09 and 0.2 ± 0.03 at 2 h post injection for the para- and the ortho-[¹⁸F]fluoro analogs of tropapride respectively. Cerebral biodistribution studies showed at 4 h a striatum uptake of 5 ± 0.7% of the injected dose per gram of striatum for the para derivative with a low fixation into the frontal cortex and the cerebellum (% ID/gFC < 0.4 and % ID/gCb < 0.3). The selectivity of 4-[¹⁸F]fluorotropapride for D₂ dopaminergic sites was demonstrated through blocking experiments with ketanserin, spiperone and halopemide. The saturability was confirmed by the use of variable specific activities. These preliminary results showed that 4-[¹⁸F]fluorotropapride can be considered as a potent radiopharmaceutical for the study of the dopaminergic system with PET.

Total photon mass attenuation coefficients of 7 fatty acids (lauric acid, palmitic acid, stearic acid, oleic acid, myristic acid, castor oil, mustard oil) have been measured in the energy range 356–1116 keV. The experimental results are analysed in terms of total cross sections, effective atomic numbers and electron densities.

Three-dimensional discrete dosimetric calculations were validated against an analytic approach for two simulated source distributions. The discrete approach was based on characterization of the source distribution by target-source distance histograms, including partial interval corrections. Using local submatrices and distance histograms, accurate dose rates were obtained for ⁹⁰Y, ¹³¹I and ⁶⁷Ga. Comparison of three- and two-dimensional calculations revealed that the latter were accurate, except for long range emitters.

The method of determination of absolute water content of a plant leaf, based upon the measured relative intensities and the mass attenuation coefficient of β-particles from ²⁰⁴Tl through the fresh and dry leaves of the plant, is described. Moisture content of plant leaves of Cotton, Sunflower, Mung and Spinach as estimated by this method agrees with the direct weighing measurements within ±4%.

A study of the background gamma radiation spectrum in Ain Shams University buildings was performed for the energy range 50 keV–3 MeV using a hyperpure Ge-detector. The absolute dose for each gamma line was calculated and an estimation of the total absorbed dose for the detected gamma lines was obtained. Comparison with other results was also performed.