The Effect of Oxygen on Impairment of the Proliferative Capacity of Human Cells in Culture by Ionizing Radiations of Different LET

Publisher Website
Google Scholar
Abstract
Oxygen-enhancement ratios (OER) have been determined for the inhibition of clone-formation by cultured cells of human origin irradiated with [alpha]-particles and deuterons of different energies, fast neutrons and 250 kvp x-rays. The results of experiments with mono-energetic charged particles, whereby narrow distributions of linear energy transfer (LET) are obtained, show that the OER decreases with increasing LET from about 2. 6 at a LET[image] of 5. 6 kev/[mu] of unit density tissue to a value of 2. 05 at 61 kev/[mu], followed by a more rapid decrease to 1. 0 at 165 kev/[mu] . With fast neutrons, produced by bombarding Be with 16 MeV deuterons, an OER of 1. 6 was obtained and with 250 kvp x-rays the OER was 2. 7. The relation between the relative biological effectiveness (RBE), the OER and the LET is discussed.