“These statistics indicate the likelihood that low doses of alpha-particle radiation protected against and reduced the incidence of lung cancer relative to the controls,” reported the researchers, based at Pacific Northwest National Laboratory, one of the Department of Energy’s 10 national laboratories.

The above is a quotation from that report you cited. And whether or not the report is serious, it illustrates one of the major problems involved with doing analytical work. And that problem has to do with assuming that data that might clearly indicate that something is happening are pointing to a certain conclusion, and not considering other possibilities.

While it is possible that low doses of alpha-particle radiation might be helping reduce the number of cases of lung cancer that could occur naturally, I suspect that if such a reduction is actually taking place it could be do to something entirely different and also possibly quite important.

The alpha-particle generating isotope or isotopes of plutonium in addition to being dangerous and poisonous radioactive substances are also basically chemicals. And it is possible that low levels of plutonium by itself, or in combination with other materials in the body can act as a cancer inhibitor. So the net result might be a small increase in cancers associated with the alpha-particle radiation added together with an even larger decrease in the number of cancers that would occur naturally.

This could be especially important in the lungs as they are exposed to more types of environmental contamination than perhaps any other body organ.

So, if plutonium metal does in fact have such a cancer inhibiting ability then medical personnel should be taking a close look at it. And since it is one of the heavier metals, if it does in fact inhibit cancer then researchers might be able to find a non-radioactive substitute for it among the other heavier elements, for example, one of its long half-life isotopes, that could accomplish the same thing.

Another possibility is that one of the chemical type byproducts of plutonium decay is actually inhibiting the cancers rather than the plutonium itself or its alpha-particles.

Additionally, I don't believe that anyone or any animal can "inhale" an alpha-particle. They are inhaling the plutonium metal or one of its compounds' dust. And the plutonium at some time emits an alpha-particle when it decays. So, that type of serious reporting error might indicate that the report could actually be ficticious.

Finally, shame on the Energy Department Officials for using beagles for research like that. Couldn't they find some ugly and unfriendly member of the canine family for their research? (humor intended)

These are personal opinions.