Radiation Dosing of CT Abdomen/Pelvis

[southerndoc]

I'm aware of the radiation risks associated with CT scans, and I often tell patients about these risks. I believe patients should be involved in the decisions for their workups, treatment, and disposition.

I've often thought that a CT of the abdomen/pelvis was about 10 mSv, and I usually tell patients this is equivalent to about 500-600 chest x-rays to offer them a perspective.

However, I recently read that it's 10 mSv for the abdominal portion and another 10 mSv for the pelvis portion.

Can someone comment on which one is accurate? As radiologists rarely see my patients, and since I'm the one ordering the exam, I think I should be familiar with this and should accurately inform patients of this when I order CT's.

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[ScooterBanks]

It's about 8-10 total for the AP. A chest is also about 8-10. A head is somewhere in the 2-4 range.

A CT chest or AP is about 500x the amount of radiation as a radiograph of the chest or KUB.

I can't stand it when the ER orders a CTA PE protocol on a 35 year old for dypsnea who has already had 5 similar negative studies over the past 2 years. I also got a CT chest/abd/pelvis on a 12 year old my last call night...when I called the ER to find out the indication, the physician told me that the "kiddo" was having palpitations and she wanted to rule out a pheo. I felt like going down to the ER and strapping her to the CT machine and scanning her brain 50 times because there was something wrong with it and I wanted to find out what it was.

 

[southerndoc]

Unfortunately in our defensive medicine society, CT's are often ordered to prevent malpractice.

 

[Neuronix]

I can't stand it when the ER orders ...

IT'S AN ER DOC IN THE RADS FORUM?! BURN THE WITCHES!

 

[Docxter]

We rarely do abdomen CTs only. Unless you are doing dedicated liver or pancreas imaging (which often involves multiple phase scans, with a multiple of increased radiation for each phase). Typically adding a pelvis to the abdomen increases the dose by approximately 50-75%. Also note that there are wide variations in dose depending on the type of machines used and the imaging protocols setup for each type of study. In practice, the best you can do is a very gross ballpark figure.