Depleted Uranium Forums (DU-BBS)

http://news.bbc.co.uk/1/hi/sci/tech/5173310.stm

Here is an interesting article on recent questioning of the Linear No Threshold (LNT) model of ionizing radiation harm. (no safe dose)

This article goes pretty far to suggest a lot of scientists are starting to think some radiation is good for us. (But not sunburns!)

This also seems to go against other scientists who say we currently underestimate the harm caused by low level radiation.

What's the real deal here? And I can't help but say I'm a bit curious just exactly how this BBC article achieved genesis.

More links on the subject:

http://www.angelfire.com/mo/radioadaptive/inthorm.html

http://en.wikipedia.org/wiki/Linear_no-threshold_model

http://en.wikipedia.org/wiki/Radiation_hormesis


Although I remember well studying the concept in my undergrad days, I'm not really sure where the biological community in general stands on the no-safe-dose question. I suspect it may not apply to alpha radiation, which consists of entire helium ions.

I hope to find the time to research this deeper.

What do you mean by safe?

That's what I remember my professor calling the LNT model -- the no-safe-dose hypothesis. In a nutshell:

If harm to DNA (mutation rates) is plotted against dose, a linear relationship can be seen that seems to point toward the [0,0] coordinate. Although it is impossible to measure data close to [0,0], scientists assumed the linear relationship held for low doses. This would imply that there was no totally safe dose. A small dose would cause a small increase in mutation. But this certainly may not be true and, perhaps, is unlikely. The cell has many DNA repair mechanisms that can probably handle any radiation-induced DNA damage below a threshold level derived from our evolution in a slightly radioactive environment. Indeed, we need mutations for evolution to work.



Still, I suspect in the case of alpha emissions at close range, the LNT hypothesis holds true due to the large size of the alpha particle and its high energy as well. I don't think cellular DNA repair mechanisms are equipped to handle even a low level of such impacts. Any comments on this?