Cerium

Cerium (Cerium, Se) is a chemical element of group III of the periodic system of elements of D. I. Mendeleyev. Serial number 58. Atomic weight (mass) 140,12.
Cerium radioactive group artificial radioactive isotopes cerium. The most important in biology and medicine are the isotopes CE141 (T1/2-32,5 day), Ce143(T1/2 - 1.4 days), Ce -144(T1/2-284,5 day). Get them out of the fission fragments of uranium (see), thorium (see) or plutonium (see) in the reactor (see nuclear Reactors). All three isotopes have the beta, and gamma rays are not very high energy (see Beta-rays, Gamma rays).
Isotopes CE141 and Behold143 used in Toxicological research, CE -144 applied applicators radiation therapy (see) skin cancer.
During the testing of nuclear weapons isotopes cerium come into the air, soil and water. In the human body cerium radioactive can penetrate the respiratory system, gastro-intestinal tract.

Cerium radioactive - isotope cerium. Cerium (Cerium, Se) is a chemical element of group III of the periodic system of elements of D. I. Mendeleyev, then. room 58, at. weight (mass) 140,12. Has 4 stable isotope.
There are several radioactive isotopes with mass numbers: 133-135, 137, 139, 141-146. Most of them produced in the fission of uranium (see), plutonium (see) and thorium (see).
In biology and medicine isotopes Se and Se widely used as radiation sources and Toxicological studies; She is used in medicine as an applicator. Se - T = 32.5 days, beta-Rashad - 0,591-0,447 MeV, 'radiation - 0,145 MeV. Se - T = 33 hours,?-radiation -1,4-0,22 MeV, 'radiation - 1,160-0,057 MeV. Se-T = 284,5 day, beta-radiation - 0,320 MeV, 'radiation - 0,134 MeV. Child product She is praseodymium Pr144 - T = 17 minutes, beta-radiation - 2,87 MeV, 'radiation -1,25; 0,695; 0,22 MeV.
At nuclear explosions isotopes cerium go on air, soil and water. In the human body radioactive cerium can penetrate the respiratory, gastrointestinal tract and through intact skin. Suction it in the gastro-intestinal tract is very small (0,05%). Through the lungs radioactive cerium absorbed in much larger quantities - from 7,28 to 9,49%. Absorption Se through the skin occurs within the first hours after exposure. After 6 hours in the skeleton comes 0,02%in the liver contains 0,002%, in the muscles - 0,12%. Radioactive cerium passes through the placenta and is excreted in the milk.
The greatest number entered isotope found in the liver (40-50%) and the skeleton (7-35%). Radioactive cerium out from the body with faeces and in small quantities in the urine.
LD50/30 for dogs at intravenous introduction Se -0,2 mccoury/g, for rabbits -0,5 mccoury/g, for rats -3, mccoury/year
The clinical picture of acute lesions animals Se characterized by antielitism, hemorrhagic syndrome, lesions of the gastrointestinal tract, degenerative-necrobiotic changes in the parenchymal organs.
In the subacute stage lesions along with pathological regeneration blood dystrophic changes of internal organs and the liver cirrhosis. In chronic defeat in dogs, rabbits, rats and mice have adenomas and sarcoma of the liver. Half of the experimental rats and rabbits develop osteosarcoma and pituitary tumors, adrenal glands, ovaries, mammary and thyroid gland, leukemia, and other Often tumors in the gastrointestinal tract and kidneys. Defeat diagnosed by beta radiation secretions and blood. The acceleration of excretion of Se carry out the introduction of pentatsin (better intravenously). Prevention and treatment - see also Radiation sickness.
Maximum permissible concentrations Se in water -3·10-9 Curie/l, in the air of working premises -6·10-13 Curie/l, in the air of the settlements -6·10-14 Curie/L.