6 ms·

> ... with people implanting rare earth magnets into the tips of their pinky fingers ... Imagine the joy of getting an MRI and forgetting about that bit of bio

by shagie 2y ago

> ... with people implanting rare earth magnets into the tips of their pinky fingers ... Imagine the joy of getting an MRI and forgetting about that bit of biohacking.

markx2 2y ago
I had an MRI. I have tragus piercings where the rings are titanium but the balls were steel. It was missed that they were there. I have surgical steel self-done implants in each hand. I have a magnet in one of my fingertips I have NFC chips in both hands. I did not explode, nothing felt hot, the only sensation was my tragus piercings wobbling slightly. This whole MRI thing ....
- hwillis 2y ago
  What matters is the field gradient. The field inside the core of the MRI is pretty homogenous, so if the metal is in there when it's switching on/off then it's fine. They will put a precautionary shield over embedded shrapnel, but it's not a big deal- it'll just wiggle a bit, and can cause some image distortion. Heating would be caused by imaging gradients, which are very small precise fields layered over the main field. Imaging gradients can switch very rapidly, which is what could cause heating, but they're so weak (fridge magnet range) that it's a nonissue. Likewise if you're more than about a meter away, the gradient has also dropped off and forces are much smaller. Imagine a bubble around the entrance to the core: that's the danger spot where field gradients can be >3 T/m. Fun fact: take B^2/(2*u0) and you get units of Pascals. Magnetic pressure and fluid pressure can be thought about pretty similarly, except that free space is very impermeable and things like iron instead act like "holes" that can create strong flows between areas of different magnetic pressure. You can have a 3 T field separated from you by air, but if you stick a steel rod into it suddenly both ends of the rod will be at 3 T. 3 T works out to about 500 psi of magnetic pressure. If you have a small, 5 mm iron sphere in a 3 T/m gradient, the pressure difference across it is only ~2.5 psi. Size matters a LOT. 2.5 psi may be a slight tug; 50 psi may pull a wire straight through you. And 10 psi may be fine when it's embedded in you already, but given a distance to accelerate it can go pretty fast.
- parhamn 2y ago
  "Don't take in ferromagnetic metals that would get pulled by a 3T magnet with 6 inches of separation" is a bit harder to grok for pretty much everyone.
  - user_7832 2y ago
    Where does the 6 inches come from? Is that the separation between the MRI machine & the patient?
- actionfromafar 2y ago
  Are you real-life Wolverine?
- willis936 2y ago
  Magnetic force drops off with the 4th power of distance. What is a slight wobble is centimeters away from being a bullet. This is pretty easy to experiment with fridge magnets to build intuition. I would exercise caution if you have embedded magnets though.
- mensetmanusman 2y ago
  Was the MRI needed to hard reset the NFC chips?
- taneq 2y ago
  Are you trying to tell me that the anal rail gun story isn’t true? I’m shocked.
- varenc 2y ago
  What’s it like having magnet in a fingertip?
  - markx2 2y ago
    It can lift a paperclip, buckyballs stick to it, and moving the fingertip across devices - spinning HD's, laptops gives a sensation when the magnetic field changes. No real practical use but I knew that.
edm0nd 2y ago
I have an implant and MRIs or Xrays cause zero issues.
- shagie 2y ago
  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848040/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848040/ > The static magnetic field B_0 of an MRI machine attracts ferromagnetic objects and accelerates them toward the center of the bore of the MRI scanner. Ferromagnetic objects such as coins, hairpins, steel oxygen tanks or scissors can be accelerated or torqued by B_0 [4,10] and become dangerous projectiles [51]. The MRI safety program of the facility needs to warn about the misconception that larger objects will resist attraction to the field and need to emphasize the relationship between object size, material components, and projectile risk. Insufficient MRI safety training of ancillary medical personnel has led to fatal accidents when medical and other equipment was accelerated into the bore of the magnet [50,51]. X-rays would be no problem. Having something that is attracted by a magnet (such as another magnet) may cause an issue. https://pubmed.ncbi.nlm.nih.gov/38128958/ https://pubmed.ncbi.nlm.nih.gov/38128958/ has more on the "stuff flying into an MRI with concerning force." Things like a 10p coin imbedding itself 0.5cm into ballistic gel. A spoon going in 3.5 cm is a bit more concerning.
  - edm0nd 2y ago
    I don't have the biomagnet implants, I have the NExT RFID + NFC chip by DangerousThings in my right hand so its not as much of a concern. Just go read straight from the source instead of linking research papers. It has the warning of: >MRI COMPATIBILITY WARNING The xG3 and all magnetic implant products should be removed before any MRI or magnetic imaging procedure. While our x-series transponders have tested as compatible with MRI machines up to 7T field strength, all magnetic products are incompatible with MRI machines and procedures. https://dangerousthings.com/product/titan/ https://dangerousthings.com/product/titan/
    - shagie 2y ago
      The comment that I originally responded to was: > with people implanting rare earth magnets into the tips of their pinky fingers And I was specifically referring to those rare earth magnets. Your comment then: > I have an implant and MRIs or Xrays cause zero issues. You gave no indication about what type of implant you hand or its manufacturer, and replying to my comment I took it in context that it was a rare earth magnet. Failing any information about the manufacturer, the information that I am able to provide to say "this can be dangerous" is research papers. You have further clarified that you only have a RFID and NFC chip implanted and not any magnets ... and provided a link to another product (rare earth magnet implant) from the same manufacturer that indicates that it is indeed dangerous when near an MRI machine which agrees with the original comment.

by shagie 2y ago

> ... with people implanting rare earth magnets into the tips of their pinky fingers ... Imagine the joy of getting an MRI and forgetting about that bit of biohacking.

markx2 2y ago

I had an MRI. I have tragus piercings where the rings are titanium but the balls were steel. It was missed that they were there. I have surgical steel self-done implants in each hand. I have a magnet in one of my fingertips I have NFC chips in both hands. I did not explode, nothing felt hot, the only sensation was my tragus piercings wobbling slightly. This whole MRI thing ....

hwillis 2y ago
What matters is the field gradient. The field inside the core of the MRI is pretty homogenous, so if the metal is in there when it's switching on/off then it's fine. They will put a precautionary shield over embedded shrapnel, but it's not a big deal- it'll just wiggle a bit, and can cause some image distortion. Heating would be caused by imaging gradients, which are very small precise fields layered over the main field. Imaging gradients can switch very rapidly, which is what could cause heating, but they're so weak (fridge magnet range) that it's a nonissue. Likewise if you're more than about a meter away, the gradient has also dropped off and forces are much smaller. Imagine a bubble around the entrance to the core: that's the danger spot where field gradients can be >3 T/m. Fun fact: take B^2/(2*u0) and you get units of Pascals. Magnetic pressure and fluid pressure can be thought about pretty similarly, except that free space is very impermeable and things like iron instead act like "holes" that can create strong flows between areas of different magnetic pressure. You can have a 3 T field separated from you by air, but if you stick a steel rod into it suddenly both ends of the rod will be at 3 T. 3 T works out to about 500 psi of magnetic pressure. If you have a small, 5 mm iron sphere in a 3 T/m gradient, the pressure difference across it is only ~2.5 psi. Size matters a LOT. 2.5 psi may be a slight tug; 50 psi may pull a wire straight through you. And 10 psi may be fine when it's embedded in you already, but given a distance to accelerate it can go pretty fast.
parhamn 2y ago
"Don't take in ferromagnetic metals that would get pulled by a 3T magnet with 6 inches of separation" is a bit harder to grok for pretty much everyone.
- user_7832 2y ago
  Where does the 6 inches come from? Is that the separation between the MRI machine & the patient?
actionfromafar 2y ago
Are you real-life Wolverine?
willis936 2y ago
Magnetic force drops off with the 4th power of distance. What is a slight wobble is centimeters away from being a bullet. This is pretty easy to experiment with fridge magnets to build intuition. I would exercise caution if you have embedded magnets though.
mensetmanusman 2y ago
Was the MRI needed to hard reset the NFC chips?
taneq 2y ago
Are you trying to tell me that the anal rail gun story isn’t true? I’m shocked.
varenc 2y ago
What’s it like having magnet in a fingertip?
- markx2 2y ago
  It can lift a paperclip, buckyballs stick to it, and moving the fingertip across devices - spinning HD's, laptops gives a sensation when the magnetic field changes. No real practical use but I knew that.

edm0nd 2y ago

I have an implant and MRIs or Xrays cause zero issues.

shagie 2y ago
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848040/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848040/ > The static magnetic field B_0 of an MRI machine attracts ferromagnetic objects and accelerates them toward the center of the bore of the MRI scanner. Ferromagnetic objects such as coins, hairpins, steel oxygen tanks or scissors can be accelerated or torqued by B_0 [4,10] and become dangerous projectiles [51]. The MRI safety program of the facility needs to warn about the misconception that larger objects will resist attraction to the field and need to emphasize the relationship between object size, material components, and projectile risk. Insufficient MRI safety training of ancillary medical personnel has led to fatal accidents when medical and other equipment was accelerated into the bore of the magnet [50,51]. X-rays would be no problem. Having something that is attracted by a magnet (such as another magnet) may cause an issue. https://pubmed.ncbi.nlm.nih.gov/38128958/ https://pubmed.ncbi.nlm.nih.gov/38128958/ has more on the "stuff flying into an MRI with concerning force." Things like a 10p coin imbedding itself 0.5cm into ballistic gel. A spoon going in 3.5 cm is a bit more concerning.
- edm0nd 2y ago
  I don't have the biomagnet implants, I have the NExT RFID + NFC chip by DangerousThings in my right hand so its not as much of a concern. Just go read straight from the source instead of linking research papers. It has the warning of: >MRI COMPATIBILITY WARNING The xG3 and all magnetic implant products should be removed before any MRI or magnetic imaging procedure. While our x-series transponders have tested as compatible with MRI machines up to 7T field strength, all magnetic products are incompatible with MRI machines and procedures. https://dangerousthings.com/product/titan/ https://dangerousthings.com/product/titan/
  - shagie 2y ago
    The comment that I originally responded to was: > with people implanting rare earth magnets into the tips of their pinky fingers And I was specifically referring to those rare earth magnets. Your comment then: > I have an implant and MRIs or Xrays cause zero issues. You gave no indication about what type of implant you hand or its manufacturer, and replying to my comment I took it in context that it was a rare earth magnet. Failing any information about the manufacturer, the information that I am able to provide to say "this can be dangerous" is research papers. You have further clarified that you only have a RFID and NFC chip implanted and not any magnets ... and provided a link to another product (rare earth magnet implant) from the same manufacturer that indicates that it is indeed dangerous when near an MRI machine which agrees with the original comment.