ABSTRACT
The Radiation-induced Adaptive Response (RAR) is a decrease of the damage effect of high doses of radiation in cells pretreated by a low (relatively nontoxic) dose of ionizing radiation with a low linear energy transfer (LET) (y-, X-rays, ~-particles with different energy from incorporated isotopes 3H, 14C and 32P). RAR has been observed in many types of mammalian cells: human lymphocytes, established cell lines and cells of several mouse tissues [1-3]. It is defined by the induction of DNA breaks, chromosome aberrations, mutation, micronuclei and cell killing. The adaptation is a rapid process which reaches its maximum in 4-6 hours after irradiation and is going on for several hours, days [1], months [4, 5] and even one year [6].
