I think it all depends on your perspective. I've worked Radiology/Cath Lab X 25 yr now (four diff't facilities), and I never find it boring. The set-up is basically the same, yes. But each pt is different, and it's rewarding to me to help the pt get through this (for the pt) high-anxiety exam.
It's an opportunity to work with the Cardiologists on a different level, and hopefully yours will enjoy teaching as much as ours do (IF you decide to work there, that is!

).
Now, taking call at age 47, when you want
lower stress, --- I'm not sure you'll accomplish lowering stress with this way

. My suggestions are:
1. Spend a day or two observing in the lab; ask questions, feel it out.
2. REALLY explore the call issue: how often would you take call (depends on how many nurses are working there, I suppose), how often do they get called in or have to stay late to finish the cases . . . And, how is call/OT compensated. If, for example, you are able to choose between taking OT $$ and putting in for comp. time, you may feel the call is worth putting up with.
Good luck with your decision (BTW, we need a cath lab nurse and don't take call ------------ yet.

).