One astonishing notion
is that low doses of radiation are not only not harmful (are you counting the negatives here?) but they're helpful. Right. Healthy. Where did this strange notion come from, and is there any evidence for it?

It came from results of some of the larger radiation studies, but before we get to that, understand that people who believe in radiation hormesis (defined) agree that large doses of radiation are harmful. It's in the low-dose area where they argue -- passionately -- that the benefits outweigh the dangers.

One proponent of radiation hormesis is John Cameron, professor emeritus of medical physics at University of Wisconsin-Madison. Cameron once believed so strongly in the dangers of low-dose radiation that he founded a company to make instruments for calibrating medical X-ray machines. His idea was that if the machines ran reliably, they could be tuned to minimize exposure to the patient.

But he's changed his tune slightly, as evidence has convinced him, at least, of the validity of "radiation hormesis." Hormesis is the theory that something that's harmful in large doses -- say table salt, magnesium, or oxygen itself -- can be beneficial in low doses. "All these trace elements -- fluorine, cobalt, iron -- are absolutely necessary in small amounts, but poisonous in larger amounts." Toxicologists have long known that "the dose makes the poison," he points out, and "it's highly likely that this is true of radiation as well.

For example, he cites a large study of more than 70,000 male shipyard workers who serviced nuclear-powered ships. The findings were comforting -- or bizarre -- depending on your point of view. Let's quote an official summary of that work:

Image courtesy of the United States Navy.

"While total mortality was lower than expected when compared to the general population, it was highest for the shipyard workers not exposed to radiation [emphasis added]. The death rates from leukemia and other blood-related cancers for both the radiation exposed and non-exposed workers were similar to those for U.S. men."

"The death rate for cancer among the radiation exposed workers was slightly lower than that for the U.S. population, but this decrease was not statistically significant. The corresponding death rate among workers not exposed to radiation was slightly higher (12 percent) due to a small increase of lung cancer."

"If somebody makes an assumption and you find a blatant case contradicting that assumption, you have to question it," Cameron says. His point is not that we should go out and expose ourselves deliberately to ionizing radiation (as was done earlier in the century), but that we should stop fearing it so much, and stop spending so much money controlling it.

For more information, see "The Good News About Radiation" in the bibliography.

An attractive idea?
Certainly, particularly to those who must spend money to control radiation exposures, in defense, medical, nuclear power, and other industries. But how much support does it get?

Suffice it to say that radiation hormesis remains a heretical notion, supported by some data, but not exactly a mainstream proposition, let alone a proven theory. Remember, many scientists are unconvinced that low-level radiation is harmless, let alone beneficial. If you just joined us, we quoted them back here.

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