Authors:V. Jovanović, R. Vukanović, T. Maksin, and M. Jovanović
The methods used for control of radiochemical purity of99mTc-MDP are presented. TLC method on silica gel, developed with methanol and acetone (11 v/v), was convenient for determination of99mTcO
with the content of 2.6±1.2%. The reliable results on detection of99mTc hydrolyzate (2.2±1.3%) and for another99mTc-MDP complex (13.2±2.8%) were obtained by application of ITLC (SA), developed with Sn-MDP. By Sephadex G-25 column chromatography (1.5 cm×5 cm) the separation of99mTcO
was not achieved. The range of normal99mTc-MDP biodistribution values in the organs of experimental animals have been determined. The mean value of bone distribution was 8.4±1.13%/g, in muscles 0.071±0.033%/g, while uptake in liver and kidneys was below 5%. Chi-square test and P show that the results on biodistribution of99mTc-MDP in liver, bones and muscles are arranged around their mean values, which is statistically allowed.
A procedure for the radiochemical purity control of99mTc-(2,3-dimercaptosuccinic acid) (DMSA), used as a renal scintigraphic agent is described. The proposed chromatographic system entails the use of two successive solvents, first MEK and second aqueous solution of 5% glycine, on the same supporting medium Gelman ITLC-SG. The procedure is fast and leads to separation and estimation of free pertechnetate, hydrolyzed form of99mTc and99mTc — DMSA. This system is superior to the others reported in the literature as the spots of the different species are more distinguished and more concentrated. Its reliability has been studied using dimercaptosuccinic acid kits of different manufacturers and the results have been checked biologically.
Authors:M. Bonardi, C. Birattari, M. Gallorini, F. Groppi, D. Arginelli, and L. Gini
The increasing concentration of Pt, Pd and Rh in the environment is mainly due to the release of these elements from the catalytic
converters of the motorvehicles. This situation makes it necessary to carry out metallotoxicological experiments on both cell
cultures and laboratory animals, in order to assess their impact on living organisms after a Long Term and Low Level Exposure
(LLE). Both nuclear reactionsnatIr(p,xn) andnatOs(α,xn) were investigated in the energy range up to 45 MeV for protons and 38 MeV for alpha-particles, in order to optimize
the irradiation parameters for the production of188,189,191Pt. Several sets of thin- and thick-target excitation functions were determined experimentally by cyclotron irradiation at
both Milano and Ispra cyclotrons. This paper reports the irradiation parameters studied and adopted and two radiochemical
procedures for the separation of radio-Pt from an Os target, as well as from ruthenium, iridium and gold impurities. These
procedures were used to obtain very high specific activity Pt radionuclides in No Carrier Added (NCA) form. Radionuclidic,
radiochemical and chemical purity measurements were carred out by the use of several techniques like ψ-spectrometry, ion-exchange
radio-chromatography, atomic absorption spectrometry and neutron activation analysis.
Authors:Z. Cheng, Q. Lin, X. Jin, F. Wang, H. Bai, D. Chen, H. Fan, and J. Du
DTPA-Octreotide(Pentetreotide), a somatostatin analogue which can bind specifically and with high affinity to somatostatin
receptor in vitro and vivo, labeled with99mTc by tin reduction in acetate buffer, has been characterized by Reverse-phase High performance Liquid Chromatography. The
effect of different solvents, mobile phase pH, linear gradient and the injected volume on the separation efficiency was evaluated.
The results show that the separation efficiency is best using μBondapak-C18 (300×3.9 mm2), linear gradient of 40% to 80% methanol (1.0 ml/min) in 0.05M acetate buffer (pH 5.5) over a 30 min period and maintaining
for another 10 min. The labeled product is a mixture which mainly consists of five components (a, b, c, d, e) successfully
proved by HPLC. Paper chromatography is also evaluated in this paper. It may be used to determine the radiochemical purity
of the labeling product, but is not a good choice for the verification each components.
Authors:M. Ayranov, A. Strezov, A. Jordanova, E. Piperkova, and S. Sergieva
The radiochemical purity of MDP and HEDP has been determined by means of gel chromatography on Sephadex and thin layer chromatography
on plastic foil silica gel. The comparison of the two radiopharmaceuticals shows equal level of complex formation with99mTc. The biodistribution demonstrated that the application of HEDP allows earlier scanning than MDP. MDP and HEDP show equal
effectivity during the clinical investigations. There is no significant difference in the radiochemical purity within six
hours after the reconstitution of the freeze-dried kits. HEDP kit demonstrates shorter period of accumulation and equivalent
complex formation levels, so it can be used in routine nuclear medicine diagnostics together with MDP kit.
The synthesis of 188Re-MAG3 is described using 188Re, which was obtained from the alumina based 188W/188Re generator. Dependence of the radiolabeling yields of 188Re-MAG3 on reducing agent concentration, Bz-MAG3 concentration, pH, temperature and incubation time was examined. In the case of optimum conditions the yield of 188Re-MAG3 was 98%. TLC and HPLC techniques were employed to monitor the different species formed. Biodistribution study of 188Re-MAG3 was carried out in rats and compared with behavior of 99mTc-MAG3.
Authors:C. Testa, D. Desideri, M. Meli, and C. Roselli
Suitable separation techniques were prepared for actinide,90Sr and226Ra determinations in environmental and industrial samples. Extraction chromatography with tri-n-octylphosphine oxide (TOPO) and di(2-ethylhexyl) phosphoric acid (HDEHP) solutions was used. IN some cases, a powder of Microthene (Microporous polyethylene) supporting solid TOPO was prepared thus obtaining a material showing better storing and column preparation features.Uranium and226Ra were determined in phosphorites, phosphoric acid and phosphogypsum.Uranium, thorium and226Ra were also measured in the low specific activity scales of hydrocarbon production equipment:226Ra was found to concentrate in some parts of the plant so causing a radiation protection problem.Plutonium and90Sr were measured either in some Mediterranean Sea samples or in environmental samples collected in Antarctica. Some interesting sea sediment profiles were also obtained.All the chemical methods were verified by: a) adding some yield tracers (232U,228Th,242Pu); b) analyzing some certified samples supplied by IAEA and NIST; c) participating in some international intercomparison runs; d) using, when possible, both an analytical and a radiometric method and e) following the radioactivity decay or growth (90Y and226Ra).
The radiochemical purity of the three osteopatic ligands:99mTc(Sn)-PyP,99mTc(Sn)-DPD and99mTc(Sn)-MDP has been determined by gel chromatography on Sephadex. The results of the analyses strongly depend on the composition of the eluent. The dilution effect of pure saline as eluent was observed in all the preparations examined. The most sensitive was found to be99mTc(Sn)-PyP. The retention of99mTc activity bound to the gel matrix (99mTc-hydrolyte) was over 30%. The diphosphonates were found to be more stable (retention 10–15%). The retention is substantially lower, i.e. a high recovery of the labeled complexes is obtained when the eluent contains the ligand. The best results are obtained when the eluent contains the same concentrations of ligand and reductant as in the labeled complex. There was no significant difference in the behavior of the given radiopharmaceuticals prepared as a fresh solution and in the freeze-dried kit.
Gentamycin sulfate (antibiotic) was labelled with99mTc with high radioactive yield. Technetium species were studied using different types of sephadex on columns. Stannous chloride was used as reducing agent for heptavalent99mTc obtained directly from generator to lower oxidation state prior to labelling. Optimal pH was found to form the most stable complex. A lyophilized kit was prepared and it was stable for more than three months. Mice, rats and rabbits have been used as exprimental animals. Accumulation of more than 20% of the labelled formula in kidneys 30 minutes post injection in rats has been found. Gamma camera images in rabbit were clear enough for kidney delineation thirty minutes after injection.
An instant kit of cysteine (amino acid) to be labelled with99mTc was prepared. Optimal conditions were found, and a procedure to prepare the kit ready to use in liophilized form to gain the highest labelling yield. More than 95% labelling yield was obtained when99mTc (TcO
) eluted from99mTc-generator was added to the contents of the kit. Each kit contains 0.66 mg of SnCl2·2H2O as stannite and 66 mg cysteine in lyophilized form. The formulation of cysteine tin (kit) was stable for nearly three months giving labelling yield more than 95%. Using GCS technique, different species of technetium and labelled cysteine were identified when Sephadex (G-50, G-25) was applied. Biodistribution of the labelled preparation revealed that kidney was the target organ. The ratio of accumulated dose in kidneys/liver was greater than 2.