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MRI Powered Pill-Sized Robot Swims Through Intestines
kkleiner writes "Researchers from Tel Aviv University in Israel and Brigham & Women's Hospital in Boston have collaborated to create a robot that can swim through the intestines. The size of a large pill, the 'microswimmer' is powered by the strong magnetic fields generated by an MRI machine. A tail measuring 20mm x 5mm made of copper and flexible polymer vibrates due to the magnets and propels the little microrobot through the gut."
In other news, the TSA has announced a new screening process involving rubber gloves and an intestinal robot. Americans should be very familiar with the procedure, as one merely has to bend over and take it.
I'm no MRI tech, but the hope is that there would be a low-power non-diagnostic routine to accommodate the little swimmer. The technology is only hype anyway, the article states that they tested it in a fish tank and haven't even tested it in a human. I doubt they'll have much success with it meandering successfully through the gut, and of course it will stop dead in its tracks when it hits that big wall of shit*.
*People who are active tend to defecate only once a day, with either hard pellets or spectacular stool length and thickness depending on how much fiber and coffee they consume.
As someone with a rather severe form of Crohns Disease, this is a godsend (and I'm saying that as an atheist!). I can assure you that anyone with a similarly debilitating intestinal disorder that inevitably leads to cancer feels the same for reasons I will spare you.
The many "score whatever funnies" that will certainly follow this story will be shamefully ignorant.
Brought to you by Carl's Junior.
Okay, so... going against every warning label on the side of an MRI machine, we're going to stick something that is metallic, magnetized, and decently sized... and put it in a person, and then put that person in the machine?
Er, ok.
The summery stated it was copper, not iron. Aluminum is commonly used for MRI safe equipment all the time. There is copper in the coils already anyhow. As long as it's nonferrous it should be fine. My question is, how long does this procedure take? MRI time is expensive, and using it mainly as a power source will have accountants heads exploding. Unless they plan to do this at night during off peak, or times when the magnet is unused. That would make perfect sense as you are paying to keep the scanner cool 24/7 anyhow.
Copper not going to fly towards the magnet like a ferromagnetic object would.
The article suggests that in a 3T machine it could move at several millimetres per minute, and 3T machines are some of the strongest devices typically installed in hospitals for human use (although there are research machines that have much stronger fields).
It's not going to fly towards the magnet at any rate.
Can't help thinking of the Bug from the Matrix.
"That's either incredibly asinine or the most brilliant troll I've ever read. Not sure which." -Anonymous Coward
I type millimetres per minute and meant to put millimetres per second in the above comment.
The article says "A swallowed pill is essentially at the mercy of the movements of the GI tract. Not so with the microswimmer." Another Googled article informs me that the colon undergoes "Segmentation contractions which chop and mix the ingesta; antiperistaltic contractions propagate toward the ileum, and giant migrating contractions... a very intense and prolonged peristaltic contraction which strips an area of large intestine clear of contents." So among other things this little gadget is swimming downstream when the colon is trying to push things upstream. What does it feel like? Tickling? Gas pains?
When you have a colonoscopy, they give you a sedative (often Midazolam), a pain-killer (often Fentanyl), and sometimes general anesthesia. Of course that's a lot more invasive, but it probably doesn't take as long because the colon is a lot shorter than your whole GI tract. Sometimes the doctor has a little trouble getting a colonscope around a tight corner. Does this thing ever get stuck and how do they deal with it?
"How to Do Nothing," kids activities, back in print!
But does it tickle?
org.slashdot.post.SignatureNotFoundException: ewg
I don't know about you guys, but I have quite a bit of air in my colon.
Having had to design surgical instruments to operate in in MRI imaging field (not just the magnetic field, but in the patient during a scan), I can answer this.
The warning on the machine is overly cautious. Almost any material can be put in in MRI, but should be tested. 99% would probably fail (and 99% of those can be predicted to fail). And who wants to test every friggin' thing someone wants to bring into an MRI room. Best just to say "NONE!"
But for stuff designed for the MRI, it's a different story.
There are 2 levels of compatibility: MRI safe and MRI compatible.
MRI safe means it won't hurt anyone. Don't use large pieces of ferro or paramagnetic materials, or the magnet will apply significant force. In other words, just don't use steel (plus a few other exotic alloys). And don't use long, thing wires, or you can create some induction heating from the radio waves (the R stands for resonance ... radio frequency resonance).
MRI compatible means that the material won't disrupt the imaging field. Either by warping the magnetic field, messing with the radio waves, or creating discontinuities (the FFT algorithms create artifacts from abrupt hydrogen density changes. Air/interface is enough sometimes).
Turns out polymers are ideal, followed by ceramics. But a small group of diamagnetic metals work pretty well too (but still have dimension and geometry constraints). Gold, silver, lead, and copper work great. BeCu alloys can be used and replace steel.
A small item (20 mm x 5 mm dia) made of copper should be MRI safe. MRI compatible is something that has to be tested, but copper/polymer objects might not screw with the image too badly if designed well. And it makes great sense to tap the radio field for a little bit of power.
The world is made by those who show up for the job.
I think that is already a solved problem for colonoscopies - 24 hours of nothing but clear liquids and jello plus aggressive laxatives, clears you right out.
I don't know about you, but the last time I tried to pick up copper with a magnet I failed. I am assuming they use the magnetic field to generate a current to move the tail.
Good news: the tiny and complex electroics in the robot may be extremely expensive, but they will be reusable.
Bad news: the robot will be reusable.
According to my butt doctor, I was "squeaky clean" when I had my colonoscopy. The previous day and a half was unpleasant, but I am grateful I went through with it.
The weirdest part of having 100% empty intestines was my lack of hunger. I had zero food or "processed food" in my guts, but I felt content like I had just eaten a decent meal but was not stuffed. Then, when I ate my first meal, I was extremely hungry despite having just eaten.
24 beers in a case, 24 hours in a day. Coincidence? I think not!
So out inside is filled with water for this little guy to swim? Anyone see how it can get stuck? Sounds pretty scary to me.
That's what I though too when I saw this. The object is basically a bullet. Software crashes and the things decides to go in a straight line to it's home position, you might have a problem.
Totally off-topic, and it's just a part of your job I suppose, but thanks for making stuff that helps people in such a direct way.
Since the MRI magnetic field is STATIC, not sure exactly how this little pill is going to move in arbitrary directions. The article isn't sufficiently detailed to answer this question. Unless they are planning to use the RF modulation energy (the same signal that has been known to burn patients in MRI's) -- not sure I'd be happy about that.
BTW, MRI scans run at least $1000-1500 for a quickie scan. So this technique sounds like it will ring up a bill of at least $5000 or more, for a session.
I kinda like the nano fuel cell idea better...
Robots get all the shitty jobs!
Yup. I find that, when I don't eat for a little while, my mind is clear. I have more energy, and I don't feel like a leaky barge with a faulty bilge pump.
The TSA is drawing from the knowledge gained by the Navy with their trained dolphin program, and starting up their own trained tapeworm program for the traveler's enjoyment.
"National Security is the chief cause of national insecurity." - Celine's First Law
Its a pretty amazing idea. How about inserting a pill with a blade on the front and setting it loose on tumors? Its a creepy idea but dying of cancer is worse.
http://michaelsmith.id.au
Most of the cost of an MRI is in making the magnetic fields precise enough to be used for imaging. Take away that requirement and I reckon you take away 90% of the price. Whats left is a powerful, controlable magnetic field generator.
You could have all sorts of fun with that.
http://michaelsmith.id.au
I'm no MRI tech, but the hope is that there would be a low-power non-diagnostic routine to accommodate the little swimmer.
No, there's no way to change the field strength in a MRI scanner. The field strength remains constant until the helium is quenched from the scanner (intentionally or accidentally). What is varied is different aspects of the RF pulse used to disrupt the magnetic field and measure the effect on the patient. But the RF is most likely not used in this case.
Great answer & explanation!!!
Thanks for making my world a bit easier to understand.
Way to go - thanks again jbeaupre (752124)!!!!!
The swimmer is POWERED by the MRI not controlled. Basically right now what they've got is a small device that has a tail that vibrates in the strong magnetic field from an MRI machine. That vibration can currently propel the device a few millimeters per second in water. That's all the article seems to say, I guess they intend to eventually put a small receiver controlling some sort of rudders as well as a camera and a small power supply? It doesn't say much about how the device will work if there isn't enough fluid for it to move through, do you just move away from the MRI and let your intestines do their job? Do you have to return the device to the hospital or do they not let you leave till you've "flushed" it out?
ok, please tell me how to POWER a device by a STATIC magnetic field. All common uses of magnetic fields for power require dynamic magnetic fields.
I give you a horseshoe magnet. Make it a motor WITHOUT anything else (no electric fields, etc).
This is genius! Think about possible extensions of this. We could have nanomanchines even going through the body killing disease and not have to worry about powering them.
DNA -- National Dyslexic Association
ok, reading the abstract of the research article provides further clues, though far from a complete explanation... "Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force." As I suspected, they have to use the RF modulation signal since a static field by itself is not suitable for generating power. The abstract mentions a 20Hz modulation -- I guess they are commandeering the regular RF signals and/or injecting a 20Hz signal on top of it. For example, such a 20Hz signal could be extracted and generating an opposing dynamic magnetic field to create the needed motor. The abstract also mentions a net 0.85mw power output of the setup. I would have to dig into the standard MRI protocols to see what this means for the RF signal, but as I mentioned, this is the same signal that, if misused can (and has) cause severe burns in patients (and subsequent lawsuits). Also still of concern is the length of time of the procedure. Its got to be at least an hour or two, which I think means at least $5000 or more in scanner time, not counted any costs for the added technology.
My family has a history of gastrointestinal disease, and I had symptoms. Hardly "unnecessary" in my case. I am grateful to have a skilled M.D. in charge of the procedure who made an accurate diagnosis (no serious problems, eat more fiber). While I may disagree with the insurance/billing side of this, the medical side was 100% spot on and I am grateful to everyone involved.
24 beers in a case, 24 hours in a day. Coincidence? I think not!
Well basically what I pulled from the article is that the entire thing is vaporware as far as what they think it might eventually do. Getting some little device with no camera and no controllers to swim in a fish tank (not in any particular direction) externally powered by an MRI machine is not at all like having a device that won't cause any harm and can actually do something useful inside a patient.
I worry this can be used as a terrible tool for torture.
that the copper wire is safe from the thieves
When I'm ill I tend not to eat for a day or two, and as I'm just starting to recover I get a similar sensation. Not quite a high, but almost. A sort of enhanced perception.
Religious fasting is quite widespread. I wonder if there's some connection?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
It sounds like this thing is using the gradients to move, and if it does that (or uses the RF) it's very unlikely it won't create an artifact. If you're going to use a field for locomotion you're going to have to distort that field locally, and that will cause a susceptibility artifact.
You know, there was a movies about something like this where a probe was manned by someone shrunk down, but this way it is manned by remote, which ends up allowing the same type of interaction....I guess we learn from our movies?!?
Obligatory 80s reference:
"Sirius Presents... PLASMANIA! HAHAHAHA"
http://www.youtube.com/watch?v=6krSk2dddaI
(it's the bloodstream, not the intestines, but still...)
Agreed. It's going to be pretty tough to avoid some sort of artifact near the probe. But it sounds like they are doing a visual inspection with the robot, using the MRI for motion and navigation.
Overall, a pretty clever idea. Future versions are bound to be even better.
The world is made by those who show up for the job.
No, not really. The field strength stays constant. Most diagnostic MRI scanners are 1.5 or 3 Tesla. Though there are 1.2T and lower open magnets and there are some 7T experimental magnets. The field causes the protons in H2O molecules to align in a specific way. A radio frequency (RF) pulse is used to disrupt this field and caused the protons alignment to change. This RF pulse is at a specific resonance frequency with the magnetic field and is tuned to the specific field strength of the scanner. Higher field magnets require higher frequency RF and will warm (cook) the patient faster. This RF pulse does cause a variance to the effect of the magnetic field on the protons. different sequences are used to measure how the protons behave when the RF is shut off and the protons relax. This is, of course an over simplification, but the point is, is that the RF pulse (which technically could be called a magnetic field) is the second field you are referring to. The overall field strength of the scanner is never changed unless there is a problem. I've seen scanners that were in use for 20+ years. Unless it's ramped down, that magnetic field is constant all of the time. If it varied, then it wouldn't be much use.
I downloaded the paper... looks like they are harvesting energy from the rf, then creating current in coils to push against the main field. It does produce a healthy artifact. They claim it's MR compatible... perhaps it is in the gut. In the brain it would be a pretty serious artifact. It does make it easy to locate though.
It's an interesting idea, but I'm not sure how practical it is. They haven't tried it in an actual intestine yet, and even if it does work, it has to compete against simpler techniques that don't require an MRI.
I'm not sure peak/offpeak hours really matter all that much. The magnet is always on, even if it's not making any sound (the gradient coils). That's why MR techs always do "the macarena" to make sure they don't have any metal before going in, even when it's quiet.
You probably wouldn't even need the gradient coils to be active for this.
:(){
I'm not sure peak/offpeak hours really matter all that much. The magnet is always on, even if it's not making any sound (the gradient coils). That's why MR techs always do "the macarena" to make sure they don't have any metal before going in, even when it's quiet.
You probably wouldn't even need the gradient coils to be active for this.
Of course it matters. during peak hours the scanner is making money by scanning for billable procedures. It is also costing you money to have the techs present as they need to be paid. Yes the magnet is always on, that's why I said you are paying to keep it cool. The He needs to be kept cold enough to be a super conductor 24/7. I would also guess that running the gradients would be undesirable for this.
Bravo Slashdot! A post where Israel is mentioned and not a single mentally challenged individual went off on a tin foil hat rant about ZOG, "apartheid" and so on. I'm proud that there was only one blatant Jew hate post.
not true about active people and defecation. :P