| Abstrakt: |
The authors present a brief review of the results of many-year research into the clinical effects, consequences, and outcomes of occupational external gamma-radiation in a wide dose range. Chronic external gamma-radiation does not cause radiation-induced effects when it does not exceed the limit of the yearly dose for personnel. Tendency for cytopenia in peripheral blood (leukothrombocytopenia) appears when the maximum yearly dose is not less than 25 to 50. The conventional threshold for the development of chronic radiation disease is a maximum yearly dose of 0.73 Gy, and total (accumulated) dose of 1.43 Gy. Long-term consequences of exposure to high-dose radiation are incomplete recovery of the hemopoietic system (moderate general bone marrow hypoplasia or partial hypoplasia of granulocytopoiesis), compensated at the level of the organism, as well as a defect in the reestablishment of cell-mediated immunity in cases of high power of radiation (more than 2.5 Gy per year) and high accumulated dose (more than 4.5 Gy). Consequences of acute radiation disease were radiation-induced cataracts (a dose of not less than 4 Gy), and incomplete reestablishment of hemopoietic system according to myelograms, in sole cases. The indicator of the fact that an exposure to radiation took place is an elevated frequency of stable chromosomal aberrations in immunocompetent cells--lymphocytes--even after 45 to 50 years after the contact was discontinued. Local dermal lesions, the range and severity of which depend on the degree of the lesion in the acute period, remain long after local radiation exposures. |
