Cardiovascular effects of fission neutron or ⁶⁰Co γ exposure in the B6CF₁ mouse

In this study, the B6CF₁ mice from the JANUS program at the Argonne National Laboratory were analyzed for increased cardiovascular disease (CVD) mortality from ⁶⁰Co γ ray or fission neutron exposures administered in either a single dose or protracted weekly doses. The data used for this study represent the last studies conducted at Argonne and have been archived for at least 15 years. CVD mortality increased in a dose-dependent manner from γ rays as well as from neutron exposures. The relative biological effectiveness (RBE) for neutrons is about 4 or 5. CVD mortality appeared to be enhanced when the dose was protracted, with a DDREF (dose and dose rate effectiveness factor) in the range of 0.4-0.45 for neutron and gamma ray exposure, respectively.