Re: Article: Lung cancer screening raises OR LOWERS lung cancerrisk

[Russ Johnson <rujohnso@nmsu.edu>]

Thought I would jump in for just a moment. Just my opinions here.



Human studies of course would provide the best documentation of effect vs dose, but ethics fortunately prohibits this. Not taking into account the Nagasaki and Cherynobyl studies which I think should be done to establish at least some data. So, extrapolating from animal studies is the only viable avenue, especially if species variation can be taken into account. But even within a human population, there is a good bit of variability to cellular effects. So, I believe this will likely always remain a numbers game to an extent. Population dose is a numbers game by definintion, extrapolating from a sample group to a population in general. Accuracy depends on many variables.



Your statement about suicide/homicide by automobile was interesting. By profession, I am not only an assistant RSO and radiation safety specialist, but also a NSC certified defensive driving instructor. I have asked the question as to whether the thousands that I've taught over the years has made a measurable reduction in at least local accident rate. The jury is still out on this, but from what I've seen, any effect has been sadly lost in the "background". Oh well. Maybe I can do better with my radiation safety program.

-Russ



Susan Gawarecki wrote:



> It should be noted that many of EPA's cleanup goals for various hazardous substances are developed by reference to animal experiments, which results are then extrapolated to humans.  However, aspirin is poisonous to cats, ivermectin is poisonous to collies (but not other breeds of dogs), squirrels can safely eat poisonous mushrooms, llamas can safely eat poison ivy, and guinea pigs and hamsters react entirely differently to PCBs (it kills one but leaves the other unharmed).   Everyone knows this is a flawed system, but this is the way we do it in order to base regulations on "science."   Regarding radiation, does physical insult to cells evoke different reactions in animals vs. people?  This is a somewhat different problem than the presence or absence of receptors to a chemical or the ability or inability to safely metabolize it.

>

> Aside from questions regarding the animal models, I have a problem with "population dose" which seems to imply that if my secretary has an x-ray that it somehow increases my risk.  If epidemiologists can't coax any cause-and-effect risk relationship from doses below 125 mSv, then why assume a linear effect?  There are more important risks to spend money on reducing.  For example, around my area, about every week some 18-30 year old (generally male) commits inadvertant suicide and/or homicide by automobile.  Wouldn't pouring those resources into better driver education, law enforcement, and road improvements provide a significantly reduced risk to the general population?  For the worst drivers, an out-of-work HP could be assigned to monitor his driving.

>

> My own opinions,

>

> Susan Gawarecki

>

> John Jacobus wrote:

>

> >Animal studies are useful, but may not reflect the

> >actual effects on humans.  As a physician, I assume

> >you understand the issues with animal vs. human

> >studies. As for the epidemiological, most conclude

> >that there is no adverse effect to the radiation

> >received.  It is only those who have a political

> >agenda that draw conclusions that the study authors do

> >not find.

>

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