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Radiology/ct exam for nasal polyps


QUESTION: Hello I am living in italy.
I went to have a scan for nasal polyps and sinus infections.
I would like to know about how much radiation I got.
120 kv 70mas
What does this mean in terms of radiation exposure?
They put a large and long lead jack on me.
Thank you kind regards mmichael

ANSWER: Hello, Michael.

According to this page: you received about 2 mSv for a CT Head without contrast; about the same amount as 8 months of normal background exposure. If you were scanned both with and without contrast, your exposure would be double that amount.

The facility where you had your exam done may be able to give you a more accurate estimate, if you need one. In any case, your risk of developing cancer from this one exam is low or very low.

Hope this helps,

---------- FOLLOW-UP ----------

QUESTION: Thank you for your reply.
One last question.
They put a large lead long jacket for protection
The did not  put a coller protection  for the thyroid.
Should they have done?

Hi, Michael.

In this case, a thyroid shield would have been so close to the area of interest (your sinuses), that it might have gotten in the way and obscured part of the image. Having to repeat an x-ray because the lead shielding is in the way defeats the purpose of using it in the first place.

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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