Well, unless you have lead-lined undies, I personally wouldn't let the cat sleep with me or sit on my lap for the next 3 days. No cat EVER died of a broken heart in 3 days, especially if you shower her with love and treats and what-not the rest of the time. It's not just the exposure - it's the length of time and proximity of the exposure as well. I'd gladly get an X-ray without the lead apron. I wouldn't get one every hour for 72 hours.
M might not care about sterility, but how does he feel about testicular cancer?
What if she had to be kenneled in the vet's office for 3 days? Would she die of a broken heart then? No. She'd be fine. I know you both love that cat...but honestly, there are reasons for the rules. If M insists on sleeping with the cat, I think I'd sleep in another room.
But that's me. Jabber and I don't let any of our pets EVER sleep in our bed.
OH! I almost forgot! I'm SO glad she got her treatment and is back home. Fingers crossed and prayers said for her little kitty body and soul.