[ RadSafe ] Reply to comments of Carol Marcus and Mohan Doss

[KARAM, PHILIP]

Just a couple of comments....

First - one need not invoke a conspiracy to explain the continued use of LNT. It can easily be explained by a combination of intellectual inertia, ease of implementation, and conservativism. Since epidemiological studies are inconclusive at low levels of exposure it is very hard to show that ANY model is correct - that being the case, it has seemed to make sense to use the most conservative - and easiest-to-implement - model for dose response. Again - no need to invoke a conspiracy on this point.

Second - virtually every NCRP, ICRP, IAEA, and USCEAR report that tackles the issue of low-dose response has stated that the results are not inconsistent with LNT. These reports have also largely stated that the results do not rule out other models. The bottom line is that these reports appear to start with the tenet that LNT is true and their task is not so much to test LNT as to refine the slope of the line. But I do think it's interesting that so many of these reports do acknowledge that other interpretations (e.g. hormesis, threshold) are not ruled out by the data.

Third - with respect to being paid to change one's mind or to promote a certain stance - come on. This might happen in medicine where hundreds of millions or billions of dollars are at stake when a drug is up for FDA approval, or when a few companies produce a product (such as cigarettes) that they're trying to protect. When we get down to it, the field of radiation safety is unlikely to be much affected on a practical level by the answer to this question - it certainly won't make my life much easier even if there's shown to be hermetic effects at low doses because it's highly unlikely that this discovery would affect regulations much at all. No matter what dose-response model we end up using, public dose limits are likely to remain largely unchanged - and it will still be necessary to post areas, control exposure, badge rad workers, etc. There is a lot of scientific curiosity and professional pride at stake - but not likely much more than that on a day-to-day practical level.

Finally - with respect to epiphanies. As Carol noted, a good scientist will follow the data where it leads and will draw his/her own conclusions as to what the data show. This sometimes includes changing long-held beliefs if the data shows that one was wrong in the past. My hat's off to anybody willing to do this - and to publically state their change of heart.

The bottom line is that this is a complex matter - scientifically, legally, and socially. If it were easy it wouldn't have taken so long to have this discussion. I go under the impression that most (not all) of us are honestly trying to figure it out to the best of our abilities - and that the majority of us have a fairly high degree of professional and personal integrity. One can hope that we can continue to respectfully disagree on this matter until there more epiphanies on one side of the other and, as with other scientific controversies, the matter is laid to rest.

Andy