One of the holy grails of robotic surgery is the ability to perform minimally invasive procedures guided by real-time scans from a magnetic resonance imaging, or MRI, machine. The problem is the space inside MRI scanners is tight for a person, let alone a person and a robot. What's more, these machines use very strong magnetic fields, so metal is not a good thing to place inside of them, a restriction that is certainly a problem for robots.
Now researchers at Worcester Polytechnic Institute (WPI) are developing a MRI-compatible robotic surgery tool that can overcome those limitations. Their system isn't made of metal, but instead has plastic parts and ceramic piezoelectric motors that allow it to work safely inside an MRI.
That area is uncomfortably near other important organs. Let's hope the scale on the monitor is 1:1...
(Score: 3, Insightful) by jcross on Friday July 10 2015, @06:48PM
Isn't the problem just ferromagnetic metals? Do bullets have iron in them?
I imagine the MRI machine itself has lots of metal parts, but they're probably copper and such. I hear you on the metal-in-the-patient issue, though. I used to work in a machine shop and for that reason I never want to go into an MRI if I can help it, in case there are still some bits of steel in my eyes or something. It's kind of horrific to think about what might happen.
(Score: 2, Interesting) by Ethanol-fueled on Friday July 10 2015, @08:13PM
Bingo. Most piezoelectric ceramics [wikipedia.org] in use today have a significant amount of lead in them, so much that health and environmental precautions like Hazmat disposal and dust masks are used when working with them. I know this because piezoelectric transducers with lead in their composition are used as SONAR transducers because the piezoelectric effect is bidirectional, so that an element can not only transmit but receive close to its center frequency (although many sonars use separate transmit/receive arrays).
But a quick disclaimer - my materials science and chemistry knowledge sucks ass so I can't explain when metal alloys become ceramics or gemstones or whatnot, so this would be a good place for somebody who can elaborate to do so.
(Score: 2) by Runaway1956 on Saturday July 11 2015, @12:53AM
I think you're right. The only metals I've ever seen in bullets are lead, and copper, except the military. Steel is associated with armor piercing rounds, not commonly in use by sportsmen or muggers on the street, or even by the police.
(Score: 1, Informative) by Anonymous Coward on Saturday July 11 2015, @03:20AM
There are enough bullets with steel in them out there for me not to assume it'll be OK: https://en.wikipedia.org/wiki/5.56%C3%9745mm_NATO#Performance [wikipedia.org]
It's not always easy to figure out whether something inside a patient is ferromagnetic or not.
And even if it's non magnetic if you're unlucky enough that the conductive metal is in a "right shape" it might absorb the RF energy and heat up: http://link.springer.com/chapter/10.1007%2F978-3-642-13039-7_255 [springer.com]
http://www.biomedical-engineering-online.com/content/7/1/11 [biomedical-engineering-online.com]