Last week I attended the annual meeting of the Radiologic Society of No America, in Chicago.  This is the largest annual medical convention/trade show in the world.  It is the place to be if one is interested in learning about radiation in Medicine.  I go every year.

This year the society hosted a very interesting mock malpractise trial.  It was very informative about the workings of such a trial for those who have never been through one.  For me, it was scary, because I see what a Pandoras Box radiologists are creating as we feed our nation's radiation phobia.

The plaintif in the case was a young father, who's wife had died at age 33 with breast cancer.  10 years prior to the diagnosis of her breast cancer, the wife had several episodes of chest pain over an 18 month period.  During that time she had 6 visits to the ER, and each time a CT was done to exclude pulmonary embolism( potentially lethal blood clots in the lungs.)  The plaintif was suing the radiologist who read the exams, because he never once mentioned the potential for carcinogenisis which might be associated with low dose radiation.  (They estimated the total dose around 200 mSv) He was not claiming the radiologist misread the CT scans, just a failure to warn about the risk, which he felt contributed to his wife's death from breast cancer.

The trial featured two expert witnesses for each side, a radiologist and a medical physicist.  A real judge presided, and real lawyers argued for both sides.  The jury was a group of volunteer laypeople, unfamiliar with the case.  Interestingly, when the jury was away "deliberating", their discussion was broadcast to the audience.

I find the case alarming because it ended in a hung jury.  7 for the defense, 5 for the plaintif. This is disturbing for several reasons.  First, these sounded like intelligent people, and yet 5 of them actually thought there was reasonable evidence that the CT scans contributed to the womans's breast cancer.  Second, one of the key defense arguments was that 10 years ago, discussing potential radiation risks was not the standard of care, while today it is being debated that it should be.

The last five years has seen a surge in articles about the potential risks of radiation from CT scanning, written by both radiologists and non-radiologists medical professionals. All of these articles use the Linear no threshold theory (LNT, see my page "A radiobiology primer" for an explanation) to calculate highly inflated and alarming numbers about the risks of these scans. They tend to ignore the fact there are many places in the world with background radiation levels in excess of 150 mSv per year (our back ground level is 3 mSv, so this is the number the articles like to use as a baseline or "normal" level).  In these areas every man, woman, child and fetus recieves a dose equivalent to 5 or 10 CT scans a year, with no ill effects.  In fact, in some of these areas the average lifespan is longer than ours.

They also seldom mention that no one has ever shown a genetic or carcinogenic effect in adults from low level radiation.  Quite the contrary.  British radiologists were closely monitored for nearly 100 years in terms of their radiation dose, diseases and life span. In the early years of medical radiation, large doses were common.  Since 1955, radiologists have received lower doses (still higher than non-radiologists) with no measurable ill effects.  American shipyard workers building nuclear powered ships were closely monitored in a similar manner. The study was considered "negative" because they also lived longer and had less cancer than non-nuclear shipyard workers.  It wasn't "negative".  It showed the positive effects of radiation, an essential nutrient for human life.  High doses of radiation can be harmful, but low doses are safe, and probably beneficial, just like Aspirin.

There is a push now to record the dose of radiation every patient recieves as part of the permanent record of the exam.  As I have mentioned in the page on Risks, Americans like to blame any and all misfortune on something and/or someone.  1 in 3 of us will get cancer.  Radiation, like coffee, can be shown to be weakly carcinogenic if given in high enough doses to children. "Weakly" being an increase of 1 per 1,000 people, added on to the 333 who would get it anyway.  It dosen't take much imagination to forsee that all 334 patients with cancer will want to blame something or someone for their disease. This is going to be a big field, and by recording everyone's doses (which implies there really is a significant risk) we are just fueling the fire.

Cancer is primarily a disease of aging.  If you exclude major carcinogens, like smoking, the age adjusted cancer rate has not really changed in the last century.  As we live longer, and eliminate frequent causes of death in the past, like polio, plague, strep throat and flu, more of us will die of cancer.  If low level radiation is so terrible, why haven't we seen a dramatic rise in cancers after 1000 idiotic nuclear tests?  Why do radiation workers live longer?  In fact, we will probably see a reduction in cancer in this country over the next 20 years, because our addiction to carbohydrates like french fries, donuts, bread, potato chips and Coke is accelerating the rate of diabetes, obesity and heart disease so dramaticly that our life expectancy is bound to decrease, and with it the total number of cancers.  But those who get cancer will still want to blame someone or something, and this trial shows radiation phobia is so prevalent, an intelligent jury could easily side with the victim.  Radiologists are opening pandoras box by recording insignificant doses from CT scans on adults, as if they actually could be important. 

Here is an abstract of the shipyard worker study

Bristish Journal of Radiology 100 year study