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Radiology/Worry over ct scans


My dr recently sent me in for a ct scan of my head. It was with and without contrast. I had no idea that this was 2 full scans. I went in thinking I was receiving about 2 mSv's of radiation, and my results show that it was more around 5.5 mSv's. I'm worried because everything I've read shows that head ct scans are averaged to be about 2 mSv's, and mine was almost 3 times that. I'm very anxious and worried. Please advise.

Thanks you!!

Hello, Jewel,

Yes, pretty much any imaging exam done "with and without contrast" means the same area is scanned twice; once before contrast and one (or more) times after contrast is administered. As with any radiology exam, the benefits from having the test must outweigh the risks of being exposed to ionizing radiation.

According to the chart found on this page: a dose of 4 - 6 mSv is comparable to natural background radiation for 16 months. The additional lifetime risk of fatal cancer from a CT brain w/wo contrast is low. There's no need to worry about your radiation exposure from this single exam.

Just try to minimize your radiation exposure from now on when you can and you'll be fine.

Hope this helps,


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Delia White


I am not qualified to interpret diagnostic imaging or to diagnose disease. Please consult a physician for that information. I am the photographer. I can tell you what to expect during most MRI, CT and X-ray procedures.


I now have more than 30 years experience in diagnostic imaging. My specialty is MRI. I am also very familiar with CT and the way we used to take x-rays (everything's digital now)!

I received my Bachelor of Science degree in Radiologic Technology.

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