Answer to Question #10731 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
I am 30 years old and I have received two CT (computerized tomography) scans, two MRI (magnetic resonance imaging) exams, one x ray of the abdomen, and five x rays of the chest in my life and I am afraid because of these radiation exposures.
The two CT scans were a CT of the brain with contrast and a CT of the abdomen and pelvis with and without contrast. The machine equipment for the two CT scans was General Electric Lightspeed.
The two MRI scans were an MRI of the brain and an MRI enterography with contrast.
I would like you to inform me of the approximate radiological dose in mSv for the above exams.
Based upon the information you've provided, we can only give an estimate of typical doses to patients from these procedures. Therefore, with that in mind, each head CT scan is estimated to be an average of 2.3 mSv. So the two CT scans of the head total about 4.6 mSv. Each abdominal CT scan is estimated to be an average of 10 mSv. So the two abdominal CT scans total 20 mSv. An average x ray to the abdomen is 0.7 mSv, with a range of 0.04 to 1.1 mSv (a very small dose of radiation). An average chest x ray is 0.02 mSv with a range of 0.007 to 0.05 mSv (again, a very tiny dose of radiation). An MRI creates magnetic fields, not x rays, so there is no radiation dose from the MRI scans you received.
Adding the average estimated effective doses together from the procedures you've listed, we get roughly 15.4 mSv as your estimated effective dose from the diagnostic x-ray procedures. But what does that mean? The Health Physics Society position statement for risk states that "cancer and other health effects have not been observed consistently at low doses (that is, less than 100 mSv) because the existence of a risk is so low as to not be detectable by current epidemiological data and methods." So you should rest easy that you have not been exposed to any significant radiation levels that would cause you long-term harm. And you should also understand that you received a medical benefit from these exams. The benefits from clinically indicated and properly performed imaging procedures far outweigh any theoretical risks.
Jean A. Gresick-Schugsta, DABR
Health Physics Society. Position Paper PS008-1 Risk Assessment. Rev. 1 April 1995, Rev. 2 February 2013.
Mettler Jr. FA, Huda W, Yoshizumi TT, Mahesh M. Effective doses in radiology and diagnostic nuclear medicine: A catalog. Radiology 248:254–263; 2008.