Radiation Risks of CT Scan and PET/CT Scan
In January 2013, Dr. Amy Barrington de Gonzalez - now Branch Chief Senior Investigator/Division of Cancer Epidemiology & Genetics / Radiation Epidemiology Branch at NIH had told the audience that the risk of developing cancer by the exposure to CT scan was 1% in a lifetime. She pointed out that the number of CT scans performed had increased from 3 million times in 1980 to 70 million times in 2007. She also predicted that the risk of developing cancer will increase to 3% if the CT usage continues to increase at the same pace. The number of CT scans performed had reached over 90 million times in 2019. So, the risk of getting cancer in a lifetime should have increased to more than 1%. So, I sent an email questioning to Dr. Barrington, and she replied that she and her team have been working on the subject and will be publishing the result. Dr. Barriton also pointed out that
the data from National Council on Radiation Protection and Measurements, which reports that annual non-therapeutic medical radiation dose to the US population in 2016 is 15-20% lower than it was in 2006. In 2006, the estimated average individual effective dose by CT was 1.46 mSv and it came down to 1.37 mSv in 2016 in spite the number of CT exams increased 20% from 2006 to 2016. I do not have access to the detailed report to find out the causes of the reduction. But I assume that the medical community and patients have become more aware of the risk of radiation exposure from CT. I also have noticed that there has been increased use of a low-dose CT scan.
In a 2009 study from Brigham and Women's Hospital in Boston, researchers estimated the potential risk of cancer from CT scans in 31,462 patients over 22 years. For the group as a whole, the increase in risk was slight — 0.7% above the overall lifetime risk of cancer in the United States, which is 42%. But for patients who had multiple CT scans, the increase in risk was higher, ranging from 2.7% to 12%. (In this group, 33% had received more than five CT scans; 5%, more than 22 scans; and 1%, more than 38.)
CT exam is fast, not expensive, and gives vital medical information as a diagnostic tool.
Also, as a consumer of CT exam, we should be aware that the more radiation from CT exams we go through,
the higher chance of developing cancer. We may want to keep a record of what type of CT scan we had, for example the whole body or just a specific area, and question to the doctor about the risk when the doctor orders us a CT exam.
Dr. Barrington de Gozales on Medical Radiation and cancer risk: assessing the price of progress
Radiation risk from medical imaging - Harvard Medical School
www.health.harvard.edu/cancer/radiation-risk-from-medical-imaging