Search results for "RADIOCHEMISTRY"
showing 10 items of 273 documents
Transferability of ASTM/NIST alanine–polyethylene recipe at ISS
2000
Abstract Alanine–polyethylene solid state dosimeters were prepared at Istituto Superiore di Sanita (ISS) following the recipe proposed by National Institute of Standards and Technology (NIST) with the goal of testing its transferability. Dosimeters were prepared using 95% alanine and 5% polyethylene, by weight. They are rugged and of increased sensitivity, repeatability and reproducibility as respect to the ISS alanine-paraffin pellets. Reproducibility of about 1% was obtained at 10 Gy and at 3 Gy if one single pellet or a stack of five dosimeters were used, respectively.
Effect of 99mTc elution in vivo from red cells on red cell volumes measured using autologous 99mTc-labeled red cells: comparison with 51Cr method
2020
The purpose of this work was to compare the measured red-cell volume (RCV) using sodium pertechnetate [RCV-99mTc] compared to the reference technique using sodium radiochromate [RCV-51Cr] and to assess the influence of technetium-99 elution on the RCV-99mTc value. Ten patients had simultaneous measurements of RCV-99mTc and RCV-51Cr. Elution of Tc-99m from red blood cells was 2.9% and led to an average overestimation of RCV-99mTc of 3.7%. The introduction of individual tracer elution rates in the RCV-99mTc calculation corrects this overestimation.
Oxygen isotopes in mammal bone phosphate: A new tool for paleohydrological and paleoclimatological research?
1984
Abstract Oxygen isotope analyses of water in blood of humans and domestic pigs indicate that the oxygen isotope fractionation effects between ingested water and body water are the same in all specimens of the same species. The δ 18 O of body water has been shown to vary linearly with the mean δ 18 O of local meteoric water. This conclusion also holds for the bone phosphate. Thus, δ 18 O ( PO 3− 4 ) values of unaltered fossil bones from humans and domestic pigs can be used to reconstruct the δ 18 O values of local meteoric waters during the life-times of the mammals. Such data can be used for paleohydrological and paleoclimatological studies both on land and at sea.
Depth profiling of Pu, 241Am and 137Cs in soils from southern Belarus measured by ICP-MS and alpha- and gamma-spectrometry
2003
The depth distribution of plutonium, americium, and Cs-137 originating front the 1986 accident at the Chernobyl Nuclear Power Plant (NPP) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl NPP was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 x 10(-12) g g(-1) to 6 x 10(-10) g g(-1) for plutonium and from 1.8 x 10(-13) g g(-1) to 1.6 x 10(-11) g g(-1) for americium. These concentrations correspond to specific activities of Pu239+240 of…
A no-carrier-added 72Se/72As radionuclide generator based on distillation
2004
Abstract Arsenic-72 is a positron emitting isotope with promising properties for syntheses of 72As-labelled radiopharmaceuticals for future application in positron emission tomography. This work describes the radiochemical separation of no-carrier-added 72Se from cyclotron irradiated germanium targets and the development of a 72Se/72As radionuclide generator, avoiding the addition of any selenium carrier. Using a vertical quartz tube device, no-carrier-added 72As is nearly quantitatively released from various chloride salt solutions containing 72Se within 10 min at a temperature of 100 °C in an HCl gas flow. The kinetics of the 72Se/72As isotope generator has been studied in relation to tem…
Uranium speciation in plants
2002
The chemical characterization of the radionuclide species is essential for a reliable assessment of the migration of radionuclides and heavy metals into the geological and biological environment on the load pathway soil - plant - animal - human. Only a few is known about the speciation of uranium in plants. Therefore we investigate the change of speciation during the transfer of uranium from initial solution into plant. Various plants (lupins, dandelion e.g.) were grown in an agricultural test field and in the laboratory on contaminated soils (up to concentration of 1g U/kg soil) and as hydroponics in the uranium containing solutions (uranium concentration: 10-5 M - 10-2 M, pH: 3 - 8). For …
Validation of a method for neutron dosimetry and spectrometry using neutron activation of metal discs
2009
A technique for neutron dosimetry and spectrometry based on neutron activation of different metal discs has been studied. After exposure to a neutron field, the radionuclides produced in the discs are detected using low-level gamma-ray spectrometry and the neutron spectrum is obtained using a spectrum unfolding technique. In order to validate the method, irradiation was performed in a well-characterised (252)Cf neutron reference field. Furthermore, the detector was used to determine the neutron fluence rate and spectrum at a storage place for MOX nuclear fuel. The results of the two measurements are reported and discussed.
Combined TL and 10B-alanine ESR dosimetry for BNCT
2004
The dosimetric technique described in this paper is based on electron spin resonance (ESR) detectors using an alanine-boric compound acid enriched with 1 0 B, and beryllium oxide thermoluminescent (TL) detectors; with this combined dosimetry, it is possible to discriminate the doses due to thermal neutrons and gamma radiation in a mixed field. Irradiations were carried out inside the thermal column of a TRIGA MARK II water-pool-type research nuclear reactor, also used for Boron Neutron Capture therapy (BNCT) applications, with thermal neutron fluence from 10 9 to 10 1 4 n t h cm - 2 . The ESR dosemeters using the alanine-boron compound indicated ESR signals about 30-fold stronger than those…
Influence of radiation defects on tritium release parameters from Li2O
1998
Abstract The study of the influence of radiation defects on tritium release behavior from polycrystalline Li2O was performed by simultaneous measurements of the luminescence emission and tritium release. It was found that the radiation defects in Li2O introduced by electron irradiation cause the retention of tritium. It is thought that the tritium recovery is affected by the formation of a Li–T bond, which is tolerant of high temperatures. The retardation of tritium decreases with increasing absorbed dose in the dose range from 50 to 140 MGy. The aggregation of radiation defects at high irradiation doses is considered to be responsible for the decrease of the interaction of tritium with rad…
Neutron flux and gamma dose measurement in the BNCT irradiation facility at the TRIGA reactor of the University of Pavia
2018
Abstract University of Pavia is equipped with a TRIGA Mark II research nuclear reactor, operating at a maximum steady state power of 250 kW. It has been used for many years to support Boron Neutron Capture Therapy (BNCT) research. An irradiation facility was constructed inside the thermal column of the reactor to produce a sufficient thermal neutron flux with low epithermal and fast neutron components, and low gamma dose. In this irradiation position, the liver of two patients affected by hepatic metastases from colon carcinoma were irradiated after borated drug administration. The facility is currently used for cell cultures and small animal irradiation. Measurements campaigns have been ca…