Determination of 93Zr decay scheme and half-life

This study describes a new determination of the decay scheme and half-life of ⁹³Zr. A pure ⁹³Zr solution was obtained after chemical separation from the dissolution of an irradiated zircaloy sample. The concentration of ⁹³Zr in the solution was measured by mass spectrometry, with an isotopic dilution technique. The activity of the solution was measured by liquid scintillation counting, using an efficiency tracing method. The measurement of the activity concentration of ⁹³Nb^m by X-ray spectrometry, allowed the determination of the ⁹³Zr decay scheme and the calculation of the ⁹³Zr detection efficiency. This leads to the calculation of the decay probability of ⁹³Zr toward ⁹³Nb^m of (0.73±0.06) and to a half-life of ⁹³Zr of (1.64±0.06)×10⁶ years. These values are discussed in comparison with the evaluated values available in the literature.     

Radiochemical analysis of 41Ca and 45Ca.

The radioactive isotopes of calcium, 41Ca (t1/2 = 1.03 x 10(5) yr) and 45Ca (t1/2 = 163 d), are produced by neutron capture in the stable isotopes 40Ca and 44Ca, respectively. These radionuclides are present in the environment due to the reactions between the galactic cosmic rays and the earth's surface, and in nuclear power plants by the activation of the structural components of nuclear reactor vessels. The aim of this paper is to propose a radiochemical separation method of 41Ca and 45Ca from the other beta gamma emitters present in radioactive materials, based on selective precipitation reactions. The activities were measured by liquid scintillation counting (LSC). The obtained decontamination factors are satisfactory for each radioactive component of the initial sample in that their activities in the final product were lower than the minimum detectable activity (MDA) due to the effectiveness of the radiochemical procedure. The sensitivity of the method allows the radiological characterization of 41Ca and 45Ca content in radioactive materials.     

Radiochemical purity of various 99mTc-labelled bone-scanning agents.

The radiochemical purity of preparations for 99mTc-bone-scanning was tested using thin-layer chromatography and electrophoresis. The investigation included ten commercial kits, comprising four types of phosphorus compounds, i.e. sodium polyphosphate, sodium pyrophosphate, disodium diphosphonate, and sodium monofluorophosphate. Out-spoken differences in the content of free pertechnetate were found between the different kits. The contents in preparations from the same kit were fairly constant, but in some cases a change could be referred to the age of the 99mTc-generator or the time of analysis. No significant difference was found between preparations made from eluate with and without oxidizer. A 99mTc-tin-colloid was sporadically present in the preparations.     

钚内污染者外科截肢放化分析及活度测量

目的 为探讨钚在国人体内的滞留与分布,对一例２０年前遭钚事故污染（左手伤部可溶性钚摄入量约为７７￣１３０Ｂｑ）者因肘部发生恶性纤维组织瘤而截下的右上臂进行了放化分析。方法 将手臂按解剖部位横向锯切成８段,再将骨和软组织剥离,分别进行灰化,离子交换、电沉积制样并进行α能谱分析和活度测量。结果 在整个手臂中共测得＾２３９Ｐｕ含量为６８．５ｍＢｑ,ａ能谱分析证实手臂组织中钚的谱峰与＾２３９Ｐｕ标准源一致     

儿童踝足部辗绞伤93例临床分析

分析93例儿童足踝辗绞伤的治疗结果：儿童踝足部辗绞伤后及时诊断、治疗,能减少后遗症的发生。     

Radiochemical purity ofd,lhexamethylpropylene amine oxime and analysis of urine-excreted HMPAO decomposition species

The radiochemical purity of hexamethylproxy-propylene amine oxime (HMPAO) was determined in 16 preparations using the three-strip method. Immediately post-formulation, 90.3%±4.0% (mean ±SD) of the activity was associated with the primary lipophilic complex having an R_f of 0.45 ± 0.11. We recorded a significantly higher content of sodium pertechnetate Tc 99m in methylethyl ketone (MEK) (21.1 % ± 8.5%) than in saline (5.0%+3.7%;P<0.001). To clarify this finding, we ran sequential chromatograms (t=0, 1, 2, 3 h) and found that the primary complex steadily disappeared, with a rate constant of 0.31 h^–1. These results suggest that there is a decomposition of the primary complex during chromatography in MEK that might be responsible for the larger fraction of sodium pertechnetate Tc 99m in MEK. Eluate composition might influence the R_f of the lipophilic complex and the rate of its in vitro decomposition. In another experimental setting, we investigated^99mTc-HMPAO decomposition species in urine after application of a suspension of labelled leukocytes by performing sequential chromatographic analyses in 11 patients. At I h after application, urinary activity reflected the presence of a secondary complex (84.8%±9.2%) and sodium pertechnetate Tc 99m (15.2% ±9.2%). The values after 3 h were markedly different (91.4%±4.8% and 8.6%±4.8%;P < 0.001). Thus, urinary activity mostly consisted of a secondary complex, increasing with time.     

Radiochemical purity control of radiolabeled drugs

The risk of using only TLC in the radiochemical purity analysis of a radiolabeled drug is shown on the example of butoprozine. The combination of TLC and HPLC gives much better certainty. In case of impurities, HPLC can be used for purification.     

Radiochemical separation of carrier-free 204,206 Bi from alpha-irradiated thallium oxide target.

Alpha activation of Tl(2)O(3) target results in the formation of carrier-free 204,206 Bi. Two different radiochemical methods were used for the separation of bismuth radionuclides from the target matrix. A very high separation factor was achieved using liquid-liquid extraction (LLX) method with methyl isobutyl ketone (MIBK)-HCl system. Solid-liquid exchange adsorption was carried out using a novel inorganic ion exchanger, zirconium vanadate from HCl medium. The separation was found to be maximum around pH 2.     

Radiochemical synthesis and biodistribution of a novel maxi-K potassium channel opener.

The racemate 1, ((+/-)-(5-Chloro-2-methoxyphenyl)-1,3-dihydro-3-fluoro-6-(trifluoromethyl)- 2H-indol-2-one), is a potent, specific and novel opener of cloned large-conductance, calcium-activated (maxi-K) potassium channels. One of its enantiomers, BMS-204352 (MaxiPost), is undergoing clinical evaluation for efficacy in patients with suspected acute stroke. In the current study, we have prepared [(18)F]-labeled 1 using a silver assisted nucleophilic substitution to examine its distribution and disposition in the rat, with particular emphasis on the brain. Biodistribution studies in rats confirm that brain uptake is rapid and occurs at high levels, and indicate that a major fraction of the compound in the brain does not accumulate by a specific, saturable mechanism.     

Radiochemical purity of D,L-hexamethylpropylene amine oxime and analysis of urine-excreted HMPAO decomposition species

The radiochemical purity of hexamethylproxypropylene amine oxime (HMPAO) was determined in 16 preparations using the three-strip method. Immediately post-formulation, 90.3% +/- 4.0% (mean +/- SD) of the activity was associated with the primary lipophilic complex having an Rf of 0.45 +/- 0.11. We recorded a significantly higher content of sodium pertechnetate Tc 99m in methylethyl ketone (MEK) (21.1% +/- 8.5%) than in saline (5.0% +/- 3.7%; P less than 0.001). To clarify this finding, we ran sequential chromatograms (t = 0, 1, 2, 3 h) and found that the primary complex steadily disappeared, with a rate constant of 0.31 h-1. These results suggest that there is a decomposition of the primary complex during chromatography in MEK that might be responsible for the larger fraction of sodium pertechnetate Tc 99m in MEK. Eluate composition might influence the Rf of the lipophilic complex and the rate of its in vitro decomposition. In another experimental setting, we investigated 99mTc-HMPAO decomposition species in urine after application of a suspension of labelled leukocytes by performing sequential chromatographic analyses in 11 patients. At 1 h after application, urinary activity reflected the presence of a secondary complex (84.8% +/- 9.2%) and sodium pertechnetate Tc 99m (15.2% +/- 9.2%). The values after 3 h were markedly different (91.4% +/- 4.8% and 8.6% +/- 4.8%; P less than 0.001). Thus, urinary activity mostly consisted of a secondary complex, increasing with time.     

Radiochemical purity studies on 10 radiopharmaceuticals

Ten radiopharmaceuticals in frequent clinical use were examined for their radiochemical purity. Thin-layer chromatography, paper chromatography and electrophoresis were used. The activity of the separated components was measured in a gamma sample changer. The assumed chemical identity of the radiochemical impurities was evaluated by comparing the results with data described in the literature. For all radiopharmaceuticals tested, the radiochemical purity was found to be not lower than the value claimed by the manufacturer and to be in accordance with the requirements of the European Pharmacopoeia as far as those pharmaceuticals are listed therein.     

Radiochemical quality control of 99mTc-labeled radiopharmaceuticals

Recognizing the fact that each nuclear medicine facility should be able to perform simple radio-chemical quality tests on currently used radiopharmaceuticals, this study was undertaken to evaluate a number of radiochromatographic methods. No single ideal method exists to assess the radiochemical composition of ^99mTc-labeled antimony sulphur colloid, sulphur colloid, iron ascorbate, citrate, human serum albumin, EHDP, macroaggregates, and microspheres.It is advisable to include thin layer chromatography with both NaCl and methylethylketone for the determination of free pertechnetate in each day's program. More detailed radiochemical analysis can be performed by combining these methods with paper chromatography, paper electrophoresis, and gel filtration. It seems reasonable to regard a constant radio-chromatographic pattern as a measure for constant radiochemical quality.The four chromatographic tests lead to consistent results regarding the percentage of free pertechnetate in the radiopharmaceutical preparations. Quantitative analysis shows that the radiochemical purity for each radiopharmaceutical is unique for the chromatographic method used and needs to be defined when stated.