[Scintigraphic systems and their evaluation using computers].

M I Devishev; V V Egorov; V N Savel'ev

PubMed · 886952

[Scintigraphic systems and their evaluation using computers].

Abstract

A comparative characteristics of modern scintillation chambers manufactured by different firms is given. Basic parameters of the chambers and the methods of their appraisal effected by using computer technique are considered and results obtained by comparing major parameters of three chamber models ("Fo-Gamma III HP", "Fo-Gamma LFOV" and "Daina-2C") through experimental procedures by following a chosen method are presented. The authors come to the conclusion that the use of computer technique tends to greatly facilitate the procedure of the chambers' control and increases the significance and reliability of the scintigraphic findings.

Explore related subjects

Cobalt Radioisotopes Computers Japan Scintillation Counting Technetium United States Comparative Study English Abstract Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

M I Devishev, V V Egorov, V N Savel'ev. [Scintigraphic systems and their evaluation using computers].. https://pubmed.ncbi.nlm.nih.gov/886952/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2003

Validating riverine transport and speciation models using nuclear reactor-derived radiocobalt.

Risk assessment of intentional or accidental discharges of toxic substances into river systems requires combined hydraulic and chemical modeling. Periodic discharges of known volumes with low radioactivity by the Beznau nuclear reactor (Switzerland) serve as validation tracers for both river flow and chemical speciation simulation. Validation of the former has been achieved by comparison of modeled and measured arrival times of radiocobalt along a 65 km transect with a maximum reaction period of 24 hours. Modeled breakthrough curves coincide well with measurements collected during three field campaigns, in spite of the fact that sorption and sedimentation processes were not activated during simulation. This gives indirect evidence of inefficient cobalt sorption. Particle/solution distribution measurements carried out during breakthrough allow further validation of our speciation approach, which is based on Tableau setup of inorganic reactions combined with sorption and organic complexation. Modeled and measured speciation results confirm recent observations of enhanced complexation of cobalt with dissolved organic substances, which significantly reduces particle sorption. The large variability of conditional stability constants for sorption and complexation reactions, for sorption site densities, and for organic ligand concentrations explains the variability of published particle-solution distribution coefficients.

Cobalt Radioisotopes↗

PubMed2003

Behavior of a surface applied radionuclide and a dye tracer in structured and repacked soil monoliths.

There has been increasing evidence in recent years about the impact of soil structure on vadose zone hydrology and the distribution of surface applied chemical substances. We have carried out a combined dye and radionuclide tracer study on two monoliths from the same location, one structured and one repacked, as part of an ongoing study to investigate the link between preferential flow, leaching of surface applied substances and their distribution within the soil.A tracer solution containing 1300 Bq/L (58)Co and 0.31 micromol/L Sulforhodamine B (SB) was added with roughly constant irrigation during a period of three weeks. The dye served as a tracer for water movement within the soil and thus allowed linkage of the radiotracer ((58)Co) with the flow pattern. Both were monitored in the outflow and measured within profile sections after monolith disassembly. Preferential flow in the structured monolith promoted the bypass and transport of both tracers, although transport was impeded at depths greater than 30 cm by compacted soil and reduced hydraulic conductivity. Eighty four percent of radiocobalt and 8% of SB were found in the upper 4 cm of the structured monolith. The homogenized monolith, on the other hand, showed mostly chromatographic infiltration and a more efficient soil filtering capacity with 91% of radiocobalt and 20% SB residing in the upper 4 cm. Furthermore no tracer was found in the outflow of the homogenized monolith during normal to high irrigation or at greater depth within the monolith. We have related flow characteristics and sorption of radiotracers by quantifying dye distributions and radionuclide activities throughout the profiles. Activities within the flow paths are up to 20-times higher than those measured in the soil matrix, and a fraction of radiocobalt follows the dye tracer in spite of cobalt's low mobility. The dye can thus be used to trace radionuclide distribution within the soil block.

Cobalt Radioisotopes↗

PubMed2003

Study of induced thermoluminescence in CVD diamond film by low-energy X-rays.

For diamond film the one-hit model that is used to interpret low-energy X-ray thermoluminescence (TL) will require some modifications. After the films were irradiated with a superficial X-ray machine with different peak voltages, a two-compartment model with three parameters, the target size, the microscopic saturation factor and the high-LET saturation factor, was used to more precisely describe the TL response to X-ray with energies down to 10 kV. The microdosimetric distribution was calculated using single-event Monte Carlo code developed by authors together with EEDL cross-section data library. Some mechanistic insight into the physical aspect of radiation interaction with solid detectors can be obtained. The sensitive size in diamond was found to be about 15 nm. The saturation of one group of sublevels combined with the activation of another group of sublevels caused the relative efficiency to have a local minimum near 20 keV. The relative efficiency becomes higher below 10 keV, which is similar to the increasing relative biological effectiveness when the linear energy transfer passing through a biological system increases. The similarity made this material to be a molecular-scale dosimeter in the future.

Cobalt Radioisotopes↗