Letter to the Editor: Reply to Cohen’s response to EPA position on cancer risk from low level radiation. Dose Respon

The scientific basis for LNT has been repeatedly reviewed and supported by expert panels (BEIR, UNSCEAR, NCRP, ICRP, etc.). It rests on two main findings: (1) the epidemiological evidence on the Japanese atomic bomb sur-vivors that there is an excess risk from low-LET radiation down to doses of about 0.1 Gy, with no dramatic deviation from linearity over the dose range from about 0.1 to 2 Gy; (2) a wide consensus that even a single track of ion-izing radiation can produce clustered damage in DNA that may lead to a somatic mutation, which provides a plausible mechanism for a linear, no-threshold dose response for cancer induction at low doses. The panels have also concluded that, although anomalies may be found in some systems, the experimental data on carcinogenesis in animals are generally consistent with LNT so long as a DDREF adjustment is made in extrapolating from acute doses of greater than about 0.5-1 Gy to lower doses or to low dose rates. My paper referred to several observed biological processes, which could conceivably modulate the dose response significantly at (low-LET