CT CAT Scan Radiation OverdoseFeb 4, 2014
High-dose radiation scans, specifically computerized tomography (CT) scans, have increased significantly in the past two decades, which may be tied to increasing cancer rates, according to a new report.
In fact, exposure to medical radiation has increased more than six-fold in the period during the 1980s through 2006, according to The New York Times, citing the National Council on Radiation Protection & Measurements. CT scan radiation doses, which are a series of X-ray images from an array of angles, are between 100 and 1,000 times greater than doses seen in conventional X-rays.
While the tie between radiation and the development of cancer is not clearly understood, one CT scan will expose a patient to the same amount of radiation that has been found to be carcinogenic, according to The Times; two large clinical studies conducted in Britain and Australia have presented these risks. In fact, the British study revealed that children exposed to multiple CT scans experienced a three-fold likelihood of developing leukemia and brain cancer. A 2011 Susan G. Komen, the Institute of Medicine-sponsored report revealed that medical imaging radiation was among the leading environmental causes of breast cancer. The report also advised women to reduce their exposure to unnecessary CT scans.
Today, one in every 10 people in the United States will undergo at least one CT scan annually. This may be due to, for example, a desire for early diagnoses, improved imaging technology, advertising, and the financial interests of physicians and imaging centers, according to The Times.
A 2009 study conducted by the National Cancer Institute estimates that CT scans conducted in 2007 will lead to a potential 29,000 excess cancer cases and 14,500 excess deaths during the lifetimes of the people exposed. Taking the number of scans performed in recent years, excess lifetime cancers are reasonably expected to be in the hundreds of thousands, The Times estimates. The Times also calculated that, if today’s CT practices do not change, 3-5 percent of all future cancers may be due to medical imaging exposure.
There are no guidelines in place to ensure that scanning is conducted in the recommended lowest dose possible. Also, a New York hospital study revealed that about one-third of its patients undergoing multiple cardiac imaging tests received a cumulative effective dose that involved in excess of 100 millisieverts of radiation, which is about the radiation received in 5,000 chest X-rays. A 2013 survey of nuclear cardiologists revealed that just 7 percent of all stress tests conducted used the “stress first” protocol, which involves examining an image of the heart after exercise, before subjecting the patient to a scan at rest. “Stress first” may reduce radiation exposure by up to 75 percent, according to The Times.
Children appear to be at particular risk for future cancers from the 4 million CT scans conducted on patients under the age of 15 in the U.S. The CTs, according to a prior Bloomberg News report, may lead to about 5,000 future cancers annually, according to a study released by JAMA Pediatrics. The research also revealed that CT scans of the head, abdomen or pelvis, chest, or spine in children under the age of 14 years of age increased more than two-fold from 1996 to 2007 before it began declining through 2010. Younger patients, girls, and those who underwent CT scans of the abdomen/pelvis or the spine were at greatest risk, said the researchers, according to Bloomberg News .
Some 7 million CT tests are performed on children in this nation annually and that number increases about 10 percent each year, according to the Image Gently Campaign and the Alliance for Radiation Safety in Pediatric Imaging, which is funded by the Society for Pediatric Radiology, the American College of Radiology, and other organizations that are working toward ensuring lower radiation doses in children, Bloomberg News wrote.