Issues surrounding CT scans and related radiation exposure risks have been making news lately with a range of experts urging for better regulation over these diagnostic tests. Long-term cancer risks and radiation overdoses are just two of the issues recently linked to this type of testing. Now, Reuters reports that imaging tests often used in the treatment of pediatric cancers can lead to high radiation levels in young patients.
A study published earlier this week provided, based on a review of 150 patients being treated at one medical center in Canada, a view into how radiation can accumulate in children from imaging tests throughout their course of treatment, explained Reuters.
While studies and media reports have lately focused on increased radiation from medical imaging to adults, citing increased and broadening use of CT scans and nuclear medicine tests, the issue surrounding scans and children is worrisome. Nuclear medicine tests, explained Reuters, involve small doses of radioactive material injected into the blood. The material concentrates in the bodyâ€™s tissues and is read by specific medical cameras.
We recently wrote that the Presidentâ€™s Cancer Panel (PCP) stated that the link between environmental carcinogens and cancers are much greater than ever realized, pointing specifically to the huge increase in exposure to medical radiation. The PCP report said that a typical â€œorgan dose range for computed tomography (CT),â€ when considering multiple scans and operator administration, â€œis 5-100 mSv,â€ the same dose an â€œaverage Hiroshima bomb drop survivor who stood several thousand yards from ground zeroâ€ experienced, said DotMed.
The implications to the pediatric community are particularly complex, said Reuters. While pediatric cancer survivors experience a greater-than-normal risk of being diagnosed with another cancer later in their lives, the radiation exposure from original cancer treatments could increase the odds of additional or repeat cancers. A challenge since imaging tests are needed for diagnosing and treating childhood cancers, said Reuters.
Karen E. Thomas and colleagues at the Hospital for Sick Children in Toronto reviewed pediatric records to 2001 and discovered a wide range in â€œthe children’s cumulative radiation dose from imaging tests done over five years,â€ said Reuters. The range was from less than 1 millisievert (mSv) to 642 mSv, with the median for the study group at 61 mSv; CT scans and nuclear medicine tests comprised most of the total radiation exposure, said Reuters.
The average American is exposed to about 3 mSv of radiation annually from natural sources; for instance, â€œthe sun’s rays and radioactive substances in the ground and water,â€ said Reuters. One chest CT exposes a child to about that amount of radiation; an abdominal CT exposes a child to about 20 months of so-called â€œbackgroundâ€ radiation: Up to 5 mSv, explained Reuters.
Based on a National Academy of Science report on the biological effects of ionizing radiation, Thomas and her team concluded that 10-year-old exposed to 61 mSv of radiation from medical imaging experience a 1.2 percent increased risk of lifetime cancer; children exposed to more than 100 mSvâ€”41 percent of those studied fell into this groupâ€”could see a lifetime cancer risk increase of over two percent, said Reuters.
Imaging, which is quick and detailed, has increased significantly in the past 10 years, many times in favor of ultrasound and magnetic resonance imaging (MRI), which do not use radiation. Radiation exposure does not cause pain and damage does not generally show up immediately; its effects accumulate over time, explained the Associated Press, previously.