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At least 19 recordsLinked to original sources
PubMed1985

[Uranium, thorium and potassium contents and radioactive equilibrium states of the uranium and thorium series nuclides in phosphate rocks and phosphate fertilizers].

Uranium, thorium and potassium contents and radioactive equilibrium states of the uranium and thorium series nuclides have been studied for 2 phosphate rocks and 7 phosphate fertilizers. Uranium contents were found to be rather high (39-117 ppm) except for phosphate rock from Kola. The uranium series nuclides were found to be in various equilibration states, which can be grouped into following three categories. Almost in the equilibrium state, 238U approximately 230Th greater than 210Pb greater than 226Ra and 238U greater than 230Th greater than 210Pb greater than 226Ra. Thorium contents were found to be, in general, low and appreciable disequilibrium of the thorium series nuclides was not observed except one sample. Potassium contents were also very low (less than 0.3% K2O) except for complex fertilizers. Based on the present data, discussions were made for the radiation exposure due to phosphate fertilizers.

Alpha Particles↗
PubMed1988

Microanalytical study of thorium 232 deposits in bone marrow and liver.

Analytical microscopy was used to study the distribution and chemical composition of thorium deposits in bone marrow and liver after injection of thorium dioxide and thorium nitrate. Thorotrast (thorium dioxide) was identified as being localized in bone marrow macrophages of a patient who had undergone cerebral arteriography forty two years ago. Large thorotrast deposits were also present in liver cells. We show that non-colloidal thorium (thorium nitrate) injected in rats concentrates in a non soluble form in bone marrow macrophages, hepatocytes and Kupffer cells. These deposits of thorium associated with phosphorus can be explained by the formation of thorium phosphate in lysosomes and we demonstrate that they remain in tissue for a long time. Microanalysis was performed with ion microscopy, and electron probe microanalysis by X ray spectrometry, which can identify and localize thorium and associated elements at cellular or intracellular level.

Animals↗
PubMed1991

The efficacy of DTPA treatment after deposition of thorium nitrate in the rat lung.

The efficacy of CaDTPA and ZnDTPA, the chelating agents of choice for several actinide elements, have been evaluated after the deposition of thorium in the rat lung in widely different amounts. The results showed that: 1. When the initial mass concentration of thorium simulated human exposure to four times the annual limits on intake for 232Th, the prompt (300 or 1000 mumol kg-1 body weight at 0.02 d) or repeated (30 or 300 mumol kg-1 body weight at 0.02, 0.25, 1,2,3 d) administration of CaDTPA were at best only moderately successful for enhancing the elimination of thorium. By 7 d after exposure, the body contents of thorium were, respectively, about 74%, 65%, 90% and 74% of those present in untreated animals. 2. When the mass concentration simulated 1.7 x 10(-3) times the annual limits on intake for 232Th, the efficacy of treatment was not increased appreciably despite the substantial reduction in mass. After the repeated administration of CaDTPA at doses of 30 and 300 mumol kg-1 using the protocol above, the body contents of thorium by 7 d were, respectively, 69% and 51% of those in untreated animals. 3. Under comparable conditions, the efficacy of ZnDTPA was less than CaDTPA. The results suggest that more effective chelating agents are needed for the treatment of workers exposed to water soluble thorium compounds.

Administration, Inhalation↗
PubMedDate not supplied

Quantitative CT for determination of thorium in thorotrast patients.

The concentrations of thorium in the liver, spleen, and their efferent lymph nodes were determined in six thorotrast patients by quantitative CT scanning. Thorium concentration per CT number was calibrated by scanning a phantom that contained a known concentration of thorium nitrate solution. The total amount of thorium determined by the quantitative CT method in the liver, spleen, and lymph nodes was compared with that determined by gamma-ray measurement of the upper abdomen using a whole body counter. A linear relationship was obtained between the amount of thorium determined by the CT method and that determined by the gamma-ray measurement method, although the correlation was not high. The quantitative CT method appears to be useful for determining, with some accuracy, the concentration of thorium in the liver, spleen, and lymph nodes of thorotrast patients.

Gamma Rays↗
PubMed1990

The role of thorium in endomyocardial fibrosis.

The behaviour of thorium in animals exposed through injection, ingestion and inhalation, as well as in uranium miners, millers and the general population suggests that thorium accumulates primarily in the lung, tracheobronchial lymph nodes and skeleton; or in the liver if injected with polymeric thorium. Epidemiological studies on uranium miners, Thorotrast studies in man and animal, and studies on the toxic effects of thorium in animals suggest that there is no apparent heart diseases due to exposure to thorium in man and animal.

Animals↗
PubMed1992

Measurement of thorium isotopes and 228Ra in soft tissues and bones of a deceased Thorotrast patient.

The whole body of an individual injected with Thorotrast 36 y prior to her death was analyzed for 232Th, 228Ra, 228Th, and 230Th. Measurement of these isotopes in all tissues of the body will provide data necessary to caculate the radiation dose to individual tissues and to evaluate the risk potential associated with deposition of thorium and progeny in humans. The tissues were ashed, dissolved in acid, and the thorium isolated by ion exchange and electrodeposition. The 228Ra was determined by measuring the 0.991-MeV gamma rays associated with decay of the 228Ac daughter. It was estimated that almost all of the 232Th from the original injection was retained in the body, mostly in the tissues of the reticuloendothelial system. A total of 28 kBq (0.76 microCi) of 232Th was measured in the soft tissues and bones. The body also contained 13 kBq 228Ra, 12 kBq 228Th, and 3.9 kBq 230Th. A Thorotrastoma contained about 3.5% of the total activity. Excluding the Thorotrastoma, approximately 45% of all the activity (232Th, 228Ra, 228Th, and 230Th) was retained in the liver, 13% in the spleen, 2% in muscle, 1% in skin, slightly less than 1% in the respiratory tract, 4% in all other soft tissues, and 33% in the skeleton (bone and bone marrow). Sixty to 80% of the thorium activity in bones containing red marrow was located in the marrow. Bones containing yellow marrow had less than 40% of the thorium activity in the marrow. Highest concentrations were found in the hepatic and other abdominal lymph nodes, spleen, hilar lymph nodes, liver, trachea, and bone. Approximately 60% of the 228Ra formed from the decay of the 232Th had been excreted from the body. The 228Ra and 228Th were in approximate equilibrium throughout the body.

Aged↗
PubMed1989

[Thorium in soil, vegetables, cereals and fruit].

Thorium contents (alpha-activities of the naturally occurring isotopes Th-228, Th-230, and Th-232) were determined in soils, vegetables, cereals, and fruits. The thorium content of plants depends on the degree of contamination by soil resuspension and thus on the specific surface of the plants. The activity of the isotope Th-230 is almost the same as that of the main isotope Th-232. Th-228, with about the same activity as Th-232 in soil, increases to about 10-fold the activity in vegetables, 29-fold in sweet chestnuts and 740-fold in Brazil nuts. Thorium concentration factors from the soil to these vegetable products are calculated; they include the total concentration, not only the soluble portion of thorium.

Edible Grain↗
PubMed1992

[Thorium amd uranium in food of animal origin].

The thorium and uranium contents (alpha-activities of the natural isotopes Th-228, Th-230, Th-232, U-234, and U-238) in several samples of the meat of domestic animals, venison, and cold-blooded animals are reported. The activity of thorium and of uranium was surprisingly constant in lean meat of all the animals tested. The average activity of the main isotope of thorium was 1-2 mBq Th-232/kg fresh meat (FM) and of uranium 21-34 mBq U-238/kg FM. The lowest and highest values observed were 0.4 and 2.7 mBq Th-232/kg FM, and 9 and 41 mBq U-238/kg FM, respectively. In some internal organs distinctly higher values were obtained: 8.6 mBq Th-232/kg in cattle bones, and 51 mBq U-238/kg in hog kidneys. The highest content of U-238, 84 mBq/kg, was observed in cuttlefish (whole animal). In lean meat, the activity of the daughter isotope Th-228 was on average (by factor) two to four times higher than that of the parent isotope Th-232. In cattle bones, and in fish samples including bones, the factor was 20 and 26, respectively. The activity of the isotope Th-230 ranged between Th-232 and Th-228. In all samples investigated, the daughter isotope U-234 showed an excess activity of 19 +/- 7% as compared to the parent isotope U-238. The above nuclides were determined alpha-spectrometrically using Th-229 for thorium, and U-232 for uranium as internal standard.

Animals↗
PubMed1986

Daily intake of thorium by an Indian urban population.

Thorium intake by an urban group (Bombay) has been estimated using neutron activation followed by simple chemical separation. Daily intake of thorium via all the three sources: food, water and air, is reported in this paper. The major contribution of thorium to intake is through food (2.0 micrograms), followed by water (0.02 microgram) and air (0.02 microgram). The individual food ingredients such as cereals, pulses, vegetables, milk, etc. were also analysed for their thorium content. The cereals were found to contribute most to the daily intake.

Environmental Monitoring↗
PubMed1992

Simultaneous spectrophotometric estimation of thorium and calcium in urine.

A simple and rapid method for the simultaneous estimation of thorium and calcium in urine was developed. Thorium and calcium were coprecipitated as oxalates at pH 3-4 and were determined using Thoronol as reagent. A multi-wave-length linear regression analysis procedure was applied. Thorium recovery was found to be 78.3% +/- 5.1% (1 sigma) and that of calcium was 93.7 +/- 3.0% (1 sigma). The minimum detection limit for thorium was found to be 2.54 mBq/dm3. The analytical results of calcium agree very well with those determined by EDTA titrimetry.

Calcium↗
PubMed1990

[Determining thorium level in urine with its preliminary chromatographic extraction].

The contributors propose a radiometric technique of detecting thorium in urine. The technique is based on a prior concentrating of the nuclide on phosphate residues, with its further separation in extraction-chromatographic vessel filled with diethylhexylphosphorus acid, and reextraction with oxalic acid. Measurements were made in the hard scintillator layer at 90 percent effectiveness. Thorium chemical output was at 85 +/- 3 percent, sensitivity at 5 mBk for a sample. If the sample contained an equal quantity of uranium, the percentage of cleaning thorium from uranium was 100. The proposed technique is economical, simple to perform, and is designed for natural thorium content measurements in human organism.

Chromatography↗
PubMed1985

Thorium dioxide-related angiosarcoma of the liver. Pathomorphologic study of 29 autopsy cases.

We describe the pathomorphologic features of 29 autopsy cases of thorium dioxide-related angiosarcoma (AGS) of the liver. The average (+/- SD) latent period after thorium dioxide injection was 36.2 +/- 5.2 years. Macroscopically, thorium dioxide-related AGS was divided into four types as follows: diffuse micronodular, multinodular, massive, and mixed multinodular and massive. Diffuse-micronodular and multinodular types were the most common. Histologically, thorium dioxide-related hepatic AGS was characterized by two cell types (spindle-shaped cells and polyhedral cells) and two structural patterns (sinusoidal and solid). There was no case composed of a solid pattern only. Immunohistochemically, factor VIII-related antigen was found to be positive in the endothelial cells of normal blood vessels and in the hyperplastic endothelial cells of the sinusoids, but negative in the tumor cells. Extramedullary hematopoiesis was found in both the tumorous and nontumorous areas in four cases. Erythrophagocytosis by the tumor cells was found in three cases. In the nontumorous area, varying degrees of sinusoidal dilatation with frequent hyperplastic changes of the sinusoidal lining cells were observed in all cases. These sinusoidal changes were frequently contiguous to AGS foci and were considered as a precursor change. In addition to the dominant sinusoidal changes, nodular hepatocytic hyperplasia was observed in two cases.

Adult↗
PubMed1988

Analysis of tissue samples containing colloidal thorium dioxide (Thorotrast) or zirconium dioxide (Zirconotrast): radiochemical preparation and alpha-spectrometry.

The aim of the present study is to assess the activity of the thorium isotopes, Th-232, Th-230, and Th-228 in tissue samples containing Thorotrast or Radiozirconotrast, i.e. Th-230 and Th-228 enriched Zirconotrast, in order to enable calculations of tissue doses. Therefore: 1. a procedure was developed for radiochemical processing of these samples, and 2. a computerised alpha-spectroscopy system has been constructed for routine activity measurements. The procedure developed for sample preparation permitted complete radiochemical processing of the above tissue samples. By subsequent electrodeposition of the thorium isotopes as well as the internal isotopic tracer Th-229, almost massless sources were obtained for alpha-spectrometry. The recovery amounts to a mean of 85% and 70% for tissues containing Thorotrast and Radiozirconotrast. With regard to the great number of samples to be measured and the expected counting times of more than 1500 min, a computerised alpha-spectroscopy system with a sample conveyor has been constructed. The energy resolution is between 45 keV and 75 keV FWHM. The detection efficiency amounts to 12%. The values of the detection level for the thorium isotopes are between 1,4 mBq and 3,1 mBq.

Animals↗