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

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