Accelerated heavy particles and the lens. VIII. Comparisons between the effects of acute low doses of iron ions (190 keV/microns) and argon ions (88 keV/microns).
The nature of the RBE-LET relationship for radiation-induced effects in vivo is not well known in the high-LET range above about 100 keV/microns. Here, we compare the cataractogenic effects of acute doses of 190 keV/microns iron ions on the eyes of rats with those of 88 keV/microns argon ions. The RBEs of the two radiations cannot be distinguished statistically, both being between 50 and 200 at our lowest dose of 0.01 Gy and decreasing to between 2 and 14 at our highest dose of 0.5 Gy; these values are consistent with results obtained in vivo, both for cataractogenesis and for oncogenesis. For this end point, therefore, the RBE-LET relationship probably varies very slowly between 88 and 190 keV/microns. On the basis of these studies with acute doses of 88 and 190 keV/microns particles, the detailed distribution in LET of the very high-LET galactic cosmic-ray dose to which astronauts in deep space are exposed may not be critical for the prediction of biological hazard. Such a conclusion might simplify the task of high-LET radiation risk estimation in space.
Brenner
D J
DJ
Center for Radiological Research, Columbia University, New York, New York 10032.
Medvedovsky
C
C
Huang
Y
Y
Worgul
B V
BV
D000818:Animals; D001128:Argon; D002386:Cataract / Q000209:etiology*; D004307:Dose-Response Relationship, Radiation; D005123:Eye / Q000528:radiation effects*; D007477:Ions; D007501:Iron; D010315:Particle Accelerators; D051381:Rats
D007477:Ions; D001128:Argon; D007501:Iron