Hi Barb,
My mom has a janitorial service, she cleans offices and her doctors said that while going through treatment the fumes from the cleaners could cause her issues...so I'm not surprised to hear this from you. We've never thought about a mask, I think if you google masks, you'll probably find some maintenance masks. I'll also ask my aunt next week if she knows of any, her husband works with all kinds of chemicals and machines. The more I think about it, they must sell something like that, we've had a lot of flooding in our area, Yardley, PA, and the people who go in to clean or examine the homes must have some type of mask to protect themselves.
Good luck with the PETSCAN, you'll be in my prayers.