Answer to Question #11080 Submitted to "Ask the Experts"

Category: Nuclear Medicine Patient Issues — Diagnostic Nuclear Medicine

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


I accompanied my mother on the way home from a PET (positron emission tomography) scan and on the drive home she became incontinent. When I got home I cleaned the car seat area. Is that sufficient to reduce future exposure?


Yes, cleaning the car seat area is all you need to have done. Your mother should have removed her wet garments and washed herself and you should have washed your hands after cleaning the car. Presumably that was done for personal hygiene reasons anyway.  

The most common radioactive material used in PET scans is 18F. The amount of time it takes for half of the 18F to transform to a stable (nonradioactive) material is a little less than two hours (110 minutes). In other words, the half-life of 18F is 110 minutes. In 24 hours, the 18F would have gone through a little more than 13 half-lives. This means that only 0.011% of the original amount remains. On the rare, but occasional, instance where 18F is spilled in a hospital, one method of decontaminating is to close the room until the next work day. In your case, cleaning the seat area achieves a better result, since even though the radioactivity would not last, the urine odor would.

Kent Lambert, CHP

Answer posted on 25 August 2014. 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.