I've had them rip pens out of my pockets before, but they are becoming better shielded every year with the newer models.
The better sheilded magnets are actually more dangerous mostly because the lines of attraction are so close to the magnet that you could not pull something back out if it started getting pulled in. They are making sheilded magnets mostly because they dont have to prep the mri scan room so much which reduces construction costs. If the shrapnel is rice you probably wouldnt see it. If there are tiny metallic flakes along with the rice, those would show up. All I can say is if you are having pens rip out of you pocket and they are flying into the magnet at 60mph I wouldnt want to be your patient in the magnet when it flys in. A 1.5 tesla magnet is 30,000 times stronger than the earth's magnetic field. A sheilded magnet doesnt allow you to 'catch' it as it is pulled in because the flux lines of the field are so close together. Sorry if I got too technical, but just trying to educate a few people on MRI.
Your right, of course. I wouldn't want to be the patient either. I'm not an MRI tech, but work closely with them. Happened to me years back under the older models. Now, I just like to stay out of the room as much as possible.
About 10 years ago, talking with a nurse. She said she always got a strange sensation whenever she brought a patient down. She was well endowed. I had to ask. Yep, she wore an underwire bra.
I always thought there whould be a study... you know, a control group and everything...