Any one know about nuclear stress tests?

My grandma got a nuclear stress test for her heart today. She had a similar one a few weeks ago and was told to stay away from pregnant woman and small kids for 24 hours. The test she got today the people didn't give her a direct answer of how long she shouldn't be around pregnant women. Any one know anything about this and how long until it is safe until I can see her? She lives out of town and I was planning on seeing her this weekend. I have talked to my doctor also who says to listen to her doctor but I'm stressed that because this is a different test maybe 24 hours isn't long enough. Since her doctor didn't give her a direct answer I just want to make sure the baby is safe.