Transcript: Cancer Risk From CT Scan Radiation
The greatest radiation exposure risk comes not from the Fukushima fallout or the polonium naturally found in all seafood, but from doctors. This was the study that originally shook things up. Estimated Risks of Radiation-Induced Fatal Cancer from Pediatric CAT scans, which concluded that the best available risk estimates suggest that pediatric CT will result in significantly increased lifetime radiation risk. How increased? Well in the United States, of the approximately 600,000 abdominal and head CT scans annually performed in children under the age 15, 500 of these individuals might ultimately not just get cancer but die from cancer attributable to that CAT scan radiation. In response to this revelation, the editor in chief of the leading radiology journal admitted that radiologists have not been watching out for children.
These estimates were based on data from Japanese atomic bomb survivors, in terms of how many cancer deaths one can expect from what kind of radiation dose, but there's never been a study able to actually document the excess cancers, until now.
Turns out the X-rays released by cat scanners may be twice as carcinogenic as the higher energy gamma rays released from the atomic bombs. A few CT scans may triple the risk of brain tumors and leukemia in children. Other studies are being performed around the world to quantify the risk and should be out in the next few years. Until then what can we do? Well, first of all we should only get X-rays when absolutely necessary. Good evidence suggests that between a fifth and a half of CAT scans aren't necessary at all—they could be replaced with another type of imaging or just not done period. That's a lot of added cancer risk for no added benefit.
Now this kind of CAT scan is ok but this kind carries risks. The risk of developing cancer after a single CT scan may be as high as 1 in a 100 for a baby girl. It can take years for cancer to develop, though, so that's why the risk is lower in the elderly since they have fewer years to live. The diagnostic medical radiation dealt out in one year is estimated to cause 2,800 breast cancers among women in the United States, and 25,000 other cancers. That's doctors causing cancer.
One chest CT scan is like getting 400 chest X-rays, and a stress test heart scan can be like getting over a thousand X-rays. Doctors need to communicate the risks of these procedures. For example, the risk of a chest CT is like the risk of having a car crash during 2500 miles of highway driving or of smoking 700 cigarettes. You pick up a pack of cigarettes and there's a warning label, but then you go in for thallium heart scan, and no one minds telling you that the risk corresponds to smoking 1400 cigarettes. 1 in every 270 middle-aged women that get an angiogram may get cancer because of that one test. The best way to avoid the risks of radioactive scans is the same way to best avoid the risks of medication--living and eating healthy enough to help avoid the need for them in the first place.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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