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Radiology/CT Virtual Colonoscopy



Is it safe to have a stomach and small intestine full of water during a CT colonoscopy?

I had to do an extra cleanse before the exam and drank a lot of water, about 3 liters, 2 hours before the exam.

After the exam the tech said my stomach and small intestine were full of water in the pictures and she asked me when was the last time I had seething to drink.

I reminded her she gave me an extra cleanse that required drinking the water. She said she forgot to tell me only to drink one cup of water.

So I'm at risk here for having all that was in me during the scan?
Would I have absorbed a larger dose of radiation?

She never told me why I was only suppose to have one cup.

Hello, Steve.

Don't worry. You would not have absorbed a larger dose of radiation because of the water.

The reason you were not supposed to drink so much is because your gastrointestinal tract should be relatively empty for a Virtual Colonoscopy. Material remaining in the colon can look like polyps or obscure other details of the colon.

Because of the water in your intestines, your CT Virtual Colonoscopy was sub-optimal. Your doctor may ask you to repeat the procedure. It will depend on what the radiology report says and whether your doctor thinks the benefits of repeating the exam would outweigh the risks of having additional radiation exposure.

Alternately, if the Virtual Colonoscopy was completely ruined, your doctor may recommend having a colonoscopy the old fashioned way: with a scope.

Hope this helps,


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Delia White


Please do not ask me to diagnose or interpret images. I am not qualified to do so. I will reject all questions asking for my interpretation of images. I am the photographer, not the physician. I cannot "read" x-rays. Please consult a physician for that information. 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 and am registered as an X-ray, CT and MRI Technologist.

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