Relative Effectiveness of HZE Iron-56 Particles for the Induction of Cytogenetic Damage In Vivo

Abstract Brooks, A. L., Bao, S., Rithidech, K., Couch, L. A. and Braby, L. A. Relative Effectiveness of HZE Iron-56 Particles for the Induction of Cytogenetic Damage In Vivo. One of the risks of prolonged manned space flight is the exposure of astronauts to radiation from galactic cosmic rays, which contain heavy ions such as 56Fe. To study the effects of such exposures, experiments were conducted at the Brookhaven National Laboratory by exposing Wistar rats to high-mass, high-Z, high-energy (HZE) particles using the Alternating Gradient Synchrotron (AGS). The biological effectiveness of 56Fe ions (1000 MeV/nucleon) relative to low-LET γ rays and high-LET α particles for the induction of chromosome damage and micronuclei was determined. The mitotic index and the frequency of chromosome aberrations were evaluated in bone marrow cells, and the frequency of micronuclei was measured in cells isolated from the trachea and the deep lung. A marked delay in the entry of cells into mitosis was induced in the bone ...