Answer to Question #15024 Submitted to "Ask the Experts"
Category: Medical and Dental Patient Issues — Diagnostic X Ray and CT
The following question was answered by an expert in the appropriate field:
I took a relative for computed tomography (CT) scans of the abdomen, with and without contrast. I was in the CT room while she was being prepared for the procedure. I cannot remember, but I am worried that I may have been in the room during the CT exam. If I was in the room during the CT exam how much radiation would I have received if I was not wearing a lead apron?
I hope your relative is doing well now. It is standard practice for the CT technologist to make sure everyone is outside the room or wearing lead if inside the room during imaging. However, we know procedures are not always followed. If you were in the room without lead during the imaging, your radiation exposure would have been very low.
It is not possible to accurately estimate your dose without knowing the dose metrics from the CT scanner and where you were standing in the room. The approximate effective dose to the patient who has a CT abdomen/pelvis with and without contrast is approximately 15.4 milliSievert (mSv). The risk to the patient from the radiation is either too low to measure or doesn't exist. Anyone else in the room during imaging is only exposed to scatter radiation, which is a small fraction of the patient dose. Your dose was likely around 1 microSievert (µSv) or less, depending on where you were standing. Average natural background radiation exposures in the United States are approximately 3 mSv per year or 8.2 microSievert per day.
You don't need to worry about your radiation exposure if you were in the room during the CT scan. The dose would have been very low.
Deirdre H. Elder, MS, CHP, CMLSO