Medical Radiology and Radiation Safety. 2013. Vol. 58. No. 5. P. 5-10

RADIATION BIOLOGY

E.S. Evstratova, N.M. Kabakova, V.G. Petin

Cell Recovery from Potentially Lethal Damage after Repeated Exposure to Ionizing Radiation

Medical Radiological Research Center, Russian, Obninsk, Russia, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Purpose: To study the ability of diploid yeast cells to recover from potentially lethal radiation damage induced by repeated exposure to cells completely recovered from the previous irradiation.

Material and methods: After irradiation of diploid yeast cells with ⁶⁰Co γ-rays or ²³⁹Pu α-particles and their complete recovery from potentially lethal damage, the cells were irradiated repeatedly. The sequence of irradiation-recovery was repeated thirdly. Basing on the mathematical model of recovery, the probability of recovery per unit time and the portion of irreversibly damaged cells were quantitatively evaluated.

Results: It was shown that the part of irreversibly damaged cells increased after repeated exposure. This effect was more expressed after exposure with high LET ionizing radiation. On the contrary, the constant of recovery, characterizing the probability of recovery per unit time, didn’t depend on the number of repeated irradiation, but it slightly decreased after high LET irradiation.

Conclusion: Concluded that the decrease in the cell ability to recover from potentially lethal radiation damage, expressed in a great extent after exposure with high LET ionizing radiation, is mainly explained by the increase in the part of irreversibly damaged cells, while the recovery process itself decreased only slightly.

Key words: cell recovery, ionizing radiation, potentially lethal damage, mathematical model, irreversible component, the probability of recovery, yeast cells, repeated irradiation