Answer to Question #13550 Submitted to "Ask the Experts"

Category: Nuclear Medicine Patient Issues — Questions Concerning Domestic Animals

The following question was answered by an expert in the appropriate field:

Q

I was told not to pick up a small child or be closer than six feet to them for 24 hours following my hepatobiliary iminodiacetic acid cholecystokinin (HIDA-CCK) procedure. I would like to know if this applies to small animals too. I am really concerned as I have two cats and two dogs and they follow me around like I am a magnet. One of my cats sleeps close to me. Do I need to try to stay away from my pets for 24 hours? This will not be easy to do when they will be scratching my door and mewing or barking if I don't let them in, but I will have to find a way as I do not want to put them at any risk.

A

Let me start out by saying that whether or not you and your pets were able to follow the instructions, everyone will be fine. You don't say if you actually have small children, but if you do, they will be fine too. Here's why:

You were given a small amount of a radioactive drug to allow your doctors to see how well your bile ducts and gallbladder are working. Specifically, they were checking for the presence of gallstones that could block your bile ducts and lead to an infection that would require surgery. The radioactive drug, often a form of technetium, gives off very low levels of gamma radiation (similar to x rays) that can expose people who are close by. More than 95% of the radioactivity is eliminated from your body via the gastrointestinal system and radioactive decay within 24 hours after you received the HIDA. That is reason for the 24-hour part of the recommendation.

However, the advice to "stay away from small children for 24 hours" really means "stay away from VERY YOUNG children for 24 hours." This advice is based upon the assumption that children are more susceptible to the effects of radiation than adults, and the younger the child, the more susceptible they are. There are reasons to believe that's true. If you put that together with the assumptions that "less is better" and "it's best to be as cautious as reasonably possible," you come up with the advice you were given. If your pets are not puppies or kittens, then the "stay away" recommendation doesn't really apply to them, even if they are physically small. Finally, the level of radiation exposure to others from a HIDA-CCK exam is so low that many radiation protection experts would consider it to carry no additional risk at all, under any circumstances.

To sum it up, your pets will be fine, and I hope you got good news about the results of your HIDA-CCK procedure.

Robert E. Reiman, MSPH, MD

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