[ RadSafe ] Studies Quantify Cancer Risks From CT Scans (MSN article)

[Richard D. Urban Jr.]

http://health.msn.com/health-topics/articlepage.aspx?cp-documentid=100251079&gt1=31036
Those with more expertise than myself should weigh in on this at above article link.

Studies Quantify Cancer Risks From CT Scans
Commonly performed CT scans are exposing patients to far more radiation than previously thought and in doses that could cause tens of thousands of cancers a year, two new studies claim...

Based on the findings, reported in the Dec. 14/28 issue of the Archives of Internal Medicine, the study authors, joined by Archives editor Dr. Rita F. Redberg, are calling on clinicians to limit radiation exposure to patients.

"CT has become so quick that we are using it so commonly, and we have lowered our threshold for using it—meaning we use it for patients who really are unlikely to have any underlying disease," said Dr. Rebecca Smith-Bindman, a professor in residence in the department of radiology at the University of California, San Francisco, and lead author of one of the studies. Although it's a "fabulous diagnostic tool," she said she believes "we have lowered it to the point where there may be no benefit in some patients."... 

...In the United States, the total number of CT (or computed tomography) scans performed annually has swelled from 3 million in 1980 to nearly 70 million in 2007, according to data cited by Smith-Bindman's team... 

...In fact, the new data suggest that its overuse may be doing more harm than good...

...Smith-Bindman's team collected data from 1,119 patients who received 11 common types of CT scans performed at four San Francisco-area hospitals. For each type of CT scan, the dose of radiation varied widely within and across hospitals. There was a 13-fold variation, on average...

...The dose of radiation for a multiphase abdomen-pelvis CT study ranged from 6 to 90 millisieverts, and the average dose was 31 millisieverts. 

Ninety millisieverts, depending on how you count it, is equivalent to "many thousands of chest X-rays," Einstein said. "That's like the background radiation you and I would receive over a 30-year period; it's just a tremendously high dose from one CT scan procedure."...

...Overall, her team estimated that 29,000 future cancers could be related to scans performed in 2007, and that these cases would result in about 14,500 deaths. The highest contributors to those numbers are the scans most frequently performed, including abdomen and pelvis, chest and head exams.

It's estimated that two-thirds of the projected cancers will occur in women, primarily because of the higher frequency of use in women (60 percent) and because of higher breast and lung cancer risks from scans that expose the chest.

While the numbers may be scary, Berrington de Gonzalez said people should realize "that CT scans provide great medical benefits and that, in general, individual risks are small and should be outweighed by the benefits if the CT scan is clinically justified."...

...To ensure safe use, the authors' recommendations focus on reducing radiation dosages, eliminating unnecessary and repeat examinations, and creating searchable electronic medical records to collect and track CT studies over time...