Answer to Question #11274 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Proximity to radioactive persons

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


I am six months pregnant and have to bring my grandmother to get a positron emission tomography (PET) scan. Will that hurt my baby since my grandmother will be giving off a high dose of radiation? How far do I have to be away from her?


Thank you for your question. The radiation your grandmother will give off will not harm your baby.

Your baby won't be harmed by the radiation emitted because the amount given to the patient is small and the length of time it stays in her body is short.

If you are still nervous about being with her, I would recommend staying about 1 meter (m) away from her for the first two hours. Although I am not sure what type of radiopharmaceutical she will be given other than knowing that it is for a PET scan, the most common one used will mostly be gone within two hours.

Kelly Classic
Certified Medical Health Physicist

Quinn B, Holahan B, Aime J, St Germain J, Dauer LT. Measured dose rate constant from oncology patients administered 18F for positron emission tomography. Med Phys 39(10); 2012.

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 27 July 2015. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.