With my family history of cancer, I was sent to the radiology lab for a 3D mammogram and a MRI. Mammogram went as usual (if you've had one, you know what I mean). It's a software difference, everything else is the same for 3D.
I did have an issue with the MRI process. After you get into the lovely two piece ensemble they provide, the paramedic sticks you with a needle to insert the thing-a-ma-bob that will stay in your arm and allows them to insert the dye for contrast. No problem there, but after sitting for 15 minutes or so in the second waiting room, I started to feel lightheaded and my hands tingled. I waited a bit to see if it would pass, but instead it got worse. A tech walked by, and I got her attention and said "I think I'm going to faint". Within 1 minute I'm in a wheelchair headed towards another room. A burly paramedic lifts me onto a gurney, and I start to feel better once I'm flat. Turns out I'm one of the few that let them know ahead of time that there's an issue. He said most people just faint right outright, and they have to pick them up from the floor, check for injuries, etc. Usually end up rescheduling. I felt fine after a couple of minutes in the quiet room, then I did my 30 minutes in the machine. No problems or reactions after laying down.
Made it home, took off the small bandage over the insertion site. It's sore, but no signs of swelling, reaction, etc. Now I just have to wait for the results.