When the Cats See Too Much

It got to a point in my life when I had to list “surgery” high in my list of prized leisure time activities. Three knee, two shoulder, one gall bladder, three kidney stone, one back, etc. surgeries. I feel just fine these days, healthy as a horse (a good omen in The Year of the Horse?), but I thought that in the process of all this (add dental x-rays to the mix, lots of them), I’ve had so many CT scans and x-rays that I think I glow in the dark. Now MRIs are rather different. They don’t send traditional radiation through your body; rather they use a magnetic field to measure the relative movement of different density tissue and bone when that field is shifted on and off. MRIs don’t do it all (and cannot be used by those with possible loose metal in the body). CT scans fire sequential series of x-rays (often dozens and dozens) to create a detailed overview of the scanned body sections.

Recently, my adult son entered UCLA Medical Center for possible kidney stones. After an ultra-sound and a few other rather obvious tests, he was informed that the odds that he had such stones was very high, but if he wanted total certainty, a CT scan could be ordered. However, according the UCLA’s new protocols, there is a distinct new trend to reduce the number of CT scans that a patient experiences during a lifetime. The impact of radiation, it seems, can indeed be cumulative, and radiation has its own set of risks, not the least of which is precipitating cancer. My son smiles, declined the scan, and accepted the obvious.

“The use of medical imaging with high-dose radiation — CT scans in particular — has soared in the last 20 years. Our resulting exposure to medical radiation has increased more than sixfold between the 1980s and 2006, according to the National Council on Radiation Protection & Measurements. The radiation doses of CT scans (a series of X-ray images from multiple angles) are 100 to 1,000 times higher than conventional X-rays.

“Of course, early diagnosis thanks to medical imaging can be lifesaving. But there is distressingly little evidence of better health outcomes associated with the current high rate of scans. There is, however, evidence of its harms.

“The relationship between radiation and the development of cancer is well understood: A single CT scan exposes a patient to the amount of radiation that epidemiologic evidence shows can be cancer-causing. The risks have been demonstrated directly in two large clinical studies in Britain and Australia. In the British study, children exposed to multiple CT scans were found to be three times more likely to develop leukemia and brain cancer. In a 2011 report sponsored by Susan G. Komen, the Institute of Medicine concluded that radiation from medical imaging, and hormone therapy, the use of which has substantially declined in the last decade, were the leading environmental causes of breast cancer, and advised that women reduce their exposure to unnecessary CT scans…

“While it is difficult to know how many cancers will result from medical imaging, a 2009 study from the National Cancer Institute estimates that CT scans conducted in 2007 will cause a projected 29,000 excess cancer cases and 14,500 excess deaths over the lifetime of those exposed. Given the many scans performed over the last several years, a reasonable estimate of excess lifetime cancers would be in the hundreds of thousands. According to our calculations, unless we change our current practices, 3 percent to 5 percent of all future cancers may result from exposure to medical imaging… We know that these tests are overused. But even when they are appropriately used, they are not always done in the safest ways possible.” New York Times, January 30^th. What’s more, older equipment uses a whole lot more radiation that newer CT systems.

Whether or not your doctors and medical facilities adhere to a new philosophy of reduced radiation-based scanning, use equipment that does not require the same level of radiation as older CT units, or have alternative systems (like MRIs) that might work almost as well, you are ultimately the arbiter of your own body and what risks you are willing accept. Ask questions, and make prudent decisions accordingly.

I’m Peter Dekom, and knowledge can actually be a lifesaver!