MRI scanning equipment info needed

[JasonART]

Hi folks. I would like to ask for any advise as to a suitable material to make a large table for MRI scanning.
One of the important specifications the table must meet is, It must be 100% anti magnetic to 1.5t.
1000 kg max load. Just as important is going to be image quality.
I have considered making it out of aluminum or a 300 series stainless steel. I have been told that neither material will give me a good result. Any comments will be greatly appreciated.

 

[MagnetDave]

"anti-magnetic?" This is not a commonly used term - could you describe what you are trying to get to?

Taking a stab at it, I think you want to limit yourself to insulating materials, such as plastics, fiberglasses, and ceramics. Even non-magnetic conductors, such as aluminum and 300 SS will exhibit eddy current effects, and those will affect your results.

Eddy current effects are a byproduct of Faraday's Law - a changing magnetic field will induce an electric potential (and, in turn, a current) in ANY conductor. In a magnetic conductor, the eddy current effects are normally dominated by the ferromagnetic effects. But eddy current effects regularly happen at a noticeable level with medium-to-large magnets, when they manifest as a drag force that feels like pulling the part through oil.

 

[JasonART]

Thank you for your quick reply MagnetDave. We want to MRI scan horses.

 

[MagnetDave]

Can I assume you will have a ferrier on site to de-shoe and re-shoe the horses as necessary?

Apart from that, I would say just avoid metals on anything going IN to the MRI, and avoid ferrous metals in the room. (Bronze tooling has regrown to fill this niche market.)

 

[JasonART]

Yes they will de-shoe before they are allowed in. Bronze you say? Thats got me curious now. Thanks mate. Do you think it would not inter-fear with our scans?
I was leaning toward making the top out of a 50mm thick slab of ultra high density polyethylene but am now looking at alternatives because the only piece of UHDPE is on the other side of the world and would take 14 weeks to get here. I'm in Australia and its in Germany.

Thx.

 

[JasonART]

BTW, The main reason why I picked UHDPE is because its the only poly I have found that comes in the size I need.

Size: 1600mm x 2000mm x 50mm.
We have a good design that needs 50mm as a minimum thickness.

 

[Clyde38]

What about wood (solid, laminate, etc.)?

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http://www.linkedin.com/in/clydehancock

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[Compositepro]

My understanding of MRI is that there is a powerful dc magnetic field but the signals being measured are radio waves so materials should be non-conductive as well as non-magnetic. I would think that your best choice would be fiberglass composite. It is structurally very strong and it is easy for someone skilled in fabrication to make a large structure with no fasteners with simple or complex shapes. Think boat builder.

 

[MagnetDave]

Yes, bronze. Again, I would not send a bronze tool INTO the MRI for the same reasons you need a non-conductive table. However, they will be safe to have in the room, as they are nonmagnetic. They are sometimes also listed as "nonsparking" tools - and they are generally the preferred metal for MRI room tooling.

Wood and fiberglass are valid choices, from an EM perspective. I think you are also going to be concerned about sterilization/cleanliness as well, so you may need a non-porous material. You MIGHT be able to get away with butcher block, which you can buy whole benchtops of. Ceramic and glass are also possible, but probably prohibitively expense.

 

[sreid]

Granite. Like Tomb Stones or Surface Plates.