Do I Need to Avoid My Pregnant Wife after a Nuclear Medicine Procedure?
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Do I Need to Avoid My Pregnant Wife after a Nuclear Medicine Procedure?

By Dr. Zoomie

Hey Dr. Zoomie – I had a nuclear medicine procedure and now the doctors are telling me that I have to stay away from my pregnant wife for two weeks. What gives? Do I really pose that great a risk to our baby? And if so, should I just move out of the house entirely and stay with friends or in a hotel?

This is what I would call an “abundance of caution” to be honest. But let’s start off with how radiation affects unborn children and then we’ll see what that has to do with you.

Developing babies are more sensitive to the effects of radiation exposure than are children or adults. This is because their cells are dividing rapidly and there’s not as much time for them to repair radiation damage before they go on to divide. So a radiation exposure that an adult wouldn’t even notice might be able to induce birth defects if it’s received by a developing child. Or maybe not – the developing fetus responds differently to radiation as a pregnancy progresses; during the first few weeks post-conception there’s no need to worry at all, for the next 3-4 months the fetus is fairly sensitive to the effects of radiation, and after the 4th month the wee beastie is no more sensitive than is any other child.

Since you didn’t mention how far along your wife is in her pregnancy it’s hard to give an exact answer; having said that, I can say that it’s highly unlikely that you pose any risk to your expected baby because, at no point in the pregnancy is there a risk to the fetus from a radiation exposure of less than 5 rem, and most of the time the critical dose is even higher. And here’s the thing – when I was working as a hospital Radiation Safety Officer (RSO), we were not allowed to let nuclear medicine patients go home until we could show that no member of the public would receive a dose higher than 0.1 rem (100 mrem) and no caregiver would receive a dose higher than 0.5 rem (500 mrem). That means that, as long as your wife treats you like she would anybody she was taking care of then your wife won’t receive any more than 0.5 rem and the baby (because the skin, abdominal muscles, uterus, and amniotic fluid reduces radiation exposure) will receive even less than this…and the dose will be only a fraction of what it takes to cause problems.

So…the radiation from you will not put your child at risk. On the other hand, radiation safety is geared to something called ALARA – keeping everyone’s radiation exposure As Low As Reasonably Achievable. In your case, that means sleeping alone for a few weeks, keeping your distance, and using the guest bathroom (if you have one) until the radioactivity has left your body. And, because some types of radioactivity (iodine is a particular culprit here) can transfer from one person to another, it also means that your wife should minimize contact with anything you’ve handled for a week or two as well. Will it hurt your child if you slip up and give your wife a hug? Almost certainly not. But one could say the same about smoking a single cigarette – chances are that smoking a single cigarette won’t cause any harm…but would you light one up and give it to a small child to smoke? Probably not…this is another case where ALARA seems to be appropriate. But the key part of this is the “R” – what’s reasonable. Staying in a separate bedroom in your home is reasonable – it’s easy to do, it’ll reduce dose to the baby, and it doesn’t cost you anything. Staying with friends or family will reduce dose a little more – but not much more than staying in a second room. And staying at a hotel…that’s going to be expensive and it won’t offer any more dose reduction than staying with a friend. For me – staying in the second bedroom and following the rest of the doctor’s instructions is reasonable; moving out of the house for few weeks is not.

If you’re interested in learning more, you should contact the Health Physics Society ( and check out their Ask the Experts feature – you can read through the answers of several thousand questions (including many about radiation and pregnancy) or you can ask your own question. And for even more information – for you as well as for your doctor – there’s a CDC web page ( with more specific information.

Something else to keep in mind is that any specific answer to any question about the risk posed by radiation exposure will require calculating the radiation exposure. Doing this sort of calculation is not necessarily for the faint of heart – neither does it require a Nobel Prize-winning physicist. What it does require is a Certified Health Physicist or a medical physicist. Medical physicists can be found in most hospital radiation oncology departments; CHPs very frequently work as Radiation Safety Officers at large universities and large research and teaching hospitals. Absent a radiation dose calculation performed by a competent professional, you can’t make any informed decision when it comes to the risk of radiation injury. Among other things, this means that if your wife has to have x-rays, CT, or any other diagnostic procedures involving radiation, you can’t evaluate the possible effects until the fetal dose has been calculated. And the CHP or medical physicist will also be able to explain what the numbers mean to your OB/GYN.

The bottom line, with any administration of diagnostic radiation, is to not worry too much. During my stint as a medical RSO I calculated about 100 fetal radiation exposures from x-rays, CT scans, fluoroscopy, and nuclear medicine and there was not a single one that was high enough to hurt the developing fetus. Can it happen? Well…sure…but it takes a whole lot more dose than what most of these procedures can deliver. So if it happens – don’t panic, find someone who can help you to determine the dose your baby received, talk with the doctor, and take it from there.

And – by the way – good luck with your procedure and with whatever medical issue prompted it!

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