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06-25-2012, 08:43 AM
Obviously, Stephen, you've done it. Were there any special precautions you used??? I assume you didn't use a tripod fluid head with steel in it. Did you use one at all?
I really need to know this, as your experience sort of suggests the portents of doom may not be accurate.
Stephen
06-25-2012, 08:43 AM
I would suspect the machine was off when these were taken. Otherwise, no technician will let you near the machine when it is on. I've shot MRIs both on and off. When on, you "might" be able to be let inside the room, but probably not. Shooting through the door works or through the window, but sometimes the window has a screen mesh on it, so that presents issues. They are going to be much more concerned with the safety of the MRI than about your silly little camera and lighting equipment.Originally Posted by Stephen Williams
Personal story time. Shot an MRI back in 1988. It was an out-of-town trip and when I got back to town, I was trying to exit the parking lot at the airport. The machine wouldn't read my ticket for some reason. The gal in the ticket booth asked if I'd been near any magnets, then it dawned on me. Take EVERYTHING out of your pockets, credit cards, atm cards, parking tickets, etc., unless you want them wiped clean.
06-25-2012, 09:04 AM
Yes, definitely, the MRI will NOT be on. If nothing else, those darn things are louder than a freaking cannon. Why they make ANY noise is beyond me, why they make those loud noises is incomprehensible to me. Obviously, there's a reason.
Mark, did you use a fluid head? Any special precautions you took?
Stephen
06-25-2012, 09:08 AM
With the machine off, the only thing I was concerned about was messing up their fancy big doughnut, which brings up another question, is it the classic MRI or an open unit? With the open one, you'd have many more options about how to set up. If given the choice, I'd choose the open flavor.
Oh, to answer your question, this was pre-RED shooting, so no to the fluid head as it was stills. However, I wouldn't have an issue using a fluid head in the room.
06-25-2012, 09:49 AM
An MRI has inside a very strong static magnetic field between the poles. This is needed to align so-called magnetic moments within the human body. In addition an MRI-magnet generates a RF-field oscillating the magnetic moments in resonance. Outside the magnet there is a stray field, but it is not dangerous. To give an idea, when one holds a permanent magnet in hands, the field is locally much stronger than the stray field of an MRI. The RF field of the magnet is neither a concern. MRI is not comparable to X-ray imaging.
Technically the aluminium cover of the camera shields RF-field, but the static stray field affects all magnetic objects. That's why the magnetic stripe of a credit card, parking ticket etc. may get magnetized and the information in it blurred. And yes, there is a force between the MRI magnet and magnetic objects, such as steel parts. When the distance becomes smaller, the force increases quickly. This can be rather surprising when one gets too close, see
http://www.nytimes.com/2005/08/19/he...agewanted=all.
Notice also, if you are using RedRaid, the magnetic field could mix up the HD. Although the aluminium cover does not shield from a static magnetic field, electronics in general is not sensitive to it.
Summing up, the main risk is the magnetic forces between the magnet and ferromagnetic objects (made of iron, steel, nickel, cobalt) or between the MRI and permamemt magnets. Have no idea whether there are ferromagnetic parts within Red One or Epic.
06-25-2012, 10:54 AM
As far as I know, MRI machines are never really "off" except for maintainence. I'd say to talk with an MRI technician before you plan any shots.
06-25-2012, 01:50 PM
Exactly. My client was an MRI company, so we had access to machines that were being serviced.
06-25-2012, 02:29 PM
I have shot several times a MRI scene in hospitals both in the UK, Eire and Dubai and have never ever been allowed into the room even,you must stay outside the Faraday cage.
Even when the MRI machine is off (it is never truly off)
The only time they would allow us in the room with equipment was if the machine was being serviced....But was told that was never going to happen either :)
06-25-2012, 03:44 PM
Well, I hate all of this contradictory advice.
Some say it's no problem. Some say it won't work.
Access will not be a problem. . . we have an in with a doc, but I sure don't want to blow up my One, either.
Stephen
06-25-2012, 04:14 PM
Actually, everyone is saying pretty much the same thing, you can't go inside the room with equipment when the machine is on, which is pretty much all the time except for when it's being worked on. BTW, they can't just simply turn it off either. From what I remember, there's liquid nitrogen used to cool the magnet and it takes them a long time to get things off and back on.
The magnet can yank your equipment into itself with tremendous force. See here: http://www.simplyphysics.com/flying_objects.html
Another point of discussion as long as we're portending doom and gloom, old tattoos might be very painful if the ink used contained traces of metal, or any other metal objects in your body from say, surgery or shrapnel.
But you should be fine. To be safe, use a telephoto from the building across the street.
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