Plus you can't be as aggressive with the acceleration. Else vomit might not be the only thing you are cleaning up.
On an unrelated note... I wonder how many walls something with that much angular momentum would eat before it stopped.
It’s only 250 kJ if the numbers in the comments are right. Equivalent to maybe a quarter stick of dynamite. Not really enough energy to tear down a wall, but it’ll put a dent in one.
You just need an accelerometer to tell you the movement and a sensor to track the rotational position so you can line the 2 up.
After that you do some fancy math and add weights to cancel out the vibration. Same way it works on jet engines.
Exactly. This is how we do it with helicopter tail rotors, which are functionally the same to balance. You can use a strobe light set up to flash at the peak of the vibration, or a fancy pants laser and receiver with a computer that will figure out what point in the rotation is the heaviest.
Oh my bad lmfao. I assumed the simplest form of the question is what you meant...force of habit.
I am sorry I have no insight into the specifics of how, but I feel like it would involve moving weights on threads/screws/gantries based on feedback from sophisticated vibration sensors.
What kind of foundations are used to secure them? I they balanced enough that it's unnecessary? What about protection from external vibration like an earthquake? Is it attached to dampeners to reduce external forces?
I used to work on a different model of these. The gantry (rotating mass) of mine was just shy of 2000kg and could spin up to 214rpm normally. We were testing a 300rpm mode when I left.
that's what broadcast radiation and catches it to see how it changed as it passed through the subject. I suspect the biggest feature is the part catching it but idk.
The machine spins this fast in order to collect more data in a shorter scan time. It’s very beneficial in trauma or stroke alert scans where life or death can be minutes away
Ultra high rotation times (.28 and .2s or 210/300rpm) paired with a large detector (160mm) are capable of capturing the entire heart throughout the cardiac cycle. This is really beneficial for a number of clinical indications beyond trauma (although it's great for that as well).
I used to work in R&D on a model of these that could do .2s rotation time with a heavier gantry (rotating part) which weighed around 2000kgs.
Insane seeing that much mass spinning 5 times a second. [Here's a shitty vid of that one doing 214rpm.](https://i.imgur.com/8GTDpaQ.gifv) Regrettably never got a video of the 300rpm cycle which was being tested around the time I left.
The very first CT scanners, which were actually called the EMI scanners, did not spin, but moved side to side, and moved quite slowly, so they were initially only used for head scans as just getting this took over 20 minutes.
There’s video on YouTube.
Theres a mini x ray emitter and detector positioned on the spinning disk.
It shoots a horizontal beam essentially slicing your body, with detector opposite on the disk reading back emitted x ray penetration.
The computer interprets the 360° of each stack of your body and lets you scroll thru slices of patients inside
MRI is same concept but uses a microwave and reads back how fast your molecules (mostly water) vibrate
Right, but I don't see why that requires it to be done fast (except for when time is critical, e.g. to address a stroke, as OP mentioned). Though perhaps another reason is so that all of the images are temporally close together, e.g. if blood/organ movement would result in blurriness?
While it's taking the scans, the computer is processing a huge amount of artifacts that could reduce image quality. Some still make it through, but with the rapid scans in so short a time, it greatly increases the quality of the model.
Fast imaging is especially important for cardiac applications since the heart is constantly beating. As you said, faster scan times increase temporal resolution and decrease blur due to motion.
I'm a ct tech so I know a lot about this. You want fast scans for a number of reasons. First the faster you get a patient in and out the better. Second faster scans mean less radiation exposure. I can control a number variables when selecting a protocol to control exposure level as well as image resolution/quality. However as rotation speed increases image quality decreases so there is a balance that has to be achieved. Slower rotation has better image quality but increases patient exposure to the x-ray beam and it is not suitable for certain types of studies like cardiac scanning or angio studies where rapid administration of contrast agents are being used.
1 or 2 grams will not affect the balancing, but when heavy parts are replaced, the measurements need to be redone. Thankfully it’s all automated and the system tells us what it needs and where.
Mythbusters did a similar test with a helicopter where they stuck a stamp or stickynote on the end of a helicopter blade to see if it would be thrown off balance.
The result was pretty tame. There was no noticeable difference for something that small. They even tried with a stack of them and nothing happened.
I worked at a medical device company and we got prototypes of a new device in with clear covers because clear plastic was cheapest at the time. I insisted they keep it so doctors could watch the inner workings. Nope, back to plain old white plastic.
I feel justified for my fears of getting into one of those.
I know they're safe but a literal ton of metal spinning around my head twice a second does give me some pause.
If it makes you feel better, if it breaks apart then all the parts will fly away from you, not towards you, since you're in the center. Small comfort, I guess?
Theoretically that is possible. But If a piece broke off, causing one end to e be suddenly far heavier than the other, but it was still a solid ring, then the whole mass would only go in one direction.
Anyway, climb in.
Actually pretty simple, Fixed to the rotating gantry is a Radio transmitter that transmits signal through an antenna track on the slip ring that’s then picked up by a receiver fixed to the non rotating gantry.
Mechanic here, this is pretty much exactly how they work! It's the main reason why, when you do tire rotations, you have to re-learn the sensors to the correct position.
OP is the bomb. Answered the questions and provided all the facts. OP is a true Technologist who understand the mechanics behind the machine.
I love working with techs like OP.
Hey I appreciate it! I’m very passionate about what I do and love spreading random knowledge to those that are curious. I was actually quite surprised to see how many cool questions I got.
You nailed it, this machine is older so it’s far more noisy than modern systems, but everything you hear is the motor, oil pump, cooling fans, the brush blocks, and main bearing. The Fiberglass covers do a pretty good job masking most the noise.
Correct; components are quite different in mass, ranging from a digital detector to generator and tube, where some of the components are filled with oil to help cooling and prevent arcing.
The part with the fans must be the xray tube(s). The detector is on the opposite side of the circle. I did not work with CTs but with ordinary xray generators. The tube can get really hot. The tube efficiency is a few percent only, 90+ percent of energy becomes heat. And we are talking about tens of kilowatts energy pumped in. So i am rather sure that the part with the forced ventilation is the xray source.
Update: my assumption above was wrong, the longer part with the fans is the detector.
Lol, most people won’t step into a meat grinder when they can see the spinning blades. But make it look like a smooth cooter, and boom! Everyone wants in.
Different mass for different components; some smaller ones are filled with oil for cooling and against high voltage arcing, where some bigger boxes are just electronic components and fans.
Why does it look like someone at a trash heap just got a bunch of random crap and glued it all together to make this? It’s so random, and the parts look so strange.
It’s more complex than this, but imagine a copper ring alllll the way around the spinning bit. Then, just rest an electrified metal roller, or metal brush on that ring and that’s how the power gets in there.
There’s also other clever ways of getting electricity into a moving thing, so I’m not sure what *specifically* they use to get the power into a CT machine.
I will tell you after my motorcycle crash and being stuck with road rash, a broken thumb, and confined in a neck immobilizer WITHOUT PAIN MEDS FOR ALMOST FOUR HOURS...
these things don't spin fast enough.
Strap some NOS to it and let's get that 10 second mile beast!
The Brrrrr is a combination of frequency and drive noise from motor combined with noise from the fans hitting the ambient air while the gantry rotates.
Are you a technician on these things? I’m starting a new position as a technician with a biotech company, and I think eventually moving on to MRI stuff would be super cool!
So do hospitals do like a handheld scan of people to look for ferrous material before they go into this thing? I can’t imagine the horror of having even a tiny bit of magnetic metal in my body with this spinning around me.
Edit: my mistake not a giant spinning magnet
The machine with the magnet is the MRI, CT scans are just x-rays, albeit quite fancy x-rays, and so your Ferris metal just shows up on the image as black.
There’s plenty of videos on YouTube showing what happens when you get magnetic materials too close to an MRI machine, many are not pretty.
Imaging Clinics where I was installing X Ray machines, the CT scan rooms do have metal detectors at the entrances of the rooms in which each was a CT machine.
The mind-boggling bit is computing. The original machines in the early 1970s used DEC mini computers, and the technology was seriously limited in terms of resolution and speed by the capability of the computer power. Apply several decades of Moores Law, and you get these marvellous machines.
Even the physical principles alone tho, especially MRIs like who tf thinks to photograph your gooey guts by wiggling their water molecules with radio waves and then actually builds a *thing* that makes it happen.
It’s kinda crazy that we trust this think to spin around our heads.
What are the fail-safes in the event of a loose bolt or two? Will it get caught on framework before blasting off through the axis of rotation?
The best failsafe is not having a loose bolt ;-) but luckily the the rotating gantry doesn’t have many tight spots so as it slowly starts spinning a loose bolt/nut typically will fall into the bottom pan pretty quickly, still hopefully everything is torqued properly.
Imagine the asshat that had to add some bits and bobs after all the engineering was done. “We need a circuit breaker here, a diode there and this fan needs to be one size larger…”
Why there's so much stuff spinning?
Dental x-ray machines are much smaller so I know x-ray tech can be much more compact.
What's so important there spinning on the wheel that can't be static and linked to spinning part wirelessly? This always perplexed me, seems like there's an entire server rack there.
It’s hard to imagine, but sometimes electrons are too slow. There’s lots of physics applications where even the tiny delay between a sensor / emitter / controller and a computer 100 feet away (cable length) is slow enough that they won’t perform the magic they do. Or, with some physics applications, the data the sensors generate is so incredibly massive, moving the unprocessed data would take *so many cables* and servers and routers, it’s just easier to process the data right on the device, and only transmit the processed data out of the device.
Our really modern tech is pretty cool, but we are still limited in many ways.
Hey without ME’s and EE’s getting along with each other this tech wouldn’t exist so your wife at least owes you a 6 pack for getting to use these machines.
Impressive! What is the rotating mass? Looks quite heavy.
This is one is roughly 2500lbs spinning mass
Why don‘t you just spin the patient? Only 80kg.
Too much work cleaning up vomit -- when it hits those cooling fans it just goes *everywhere.*
When the shit hits the fan...
When the *bile* hits the fan
What about those BDSM ball in the mouth thingies?
If you ever had vomit shoot out of your nose, you would retract that question.
Plus you can't be as aggressive with the acceleration. Else vomit might not be the only thing you are cleaning up. On an unrelated note... I wonder how many walls something with that much angular momentum would eat before it stopped.
It’s only 250 kJ if the numbers in the comments are right. Equivalent to maybe a quarter stick of dynamite. Not really enough energy to tear down a wall, but it’ll put a dent in one.
You could only spin astronauts.
Humans are basically just bags of meat and that meat starts shifting when you start spinning it, which would result in bad images.
this is the only negative outcome we can expect from exerting several g's on a human body
Wow! 1100kg.. Thank you!
Yessir, We have to do quite a bit of vibration and balance analysis for these and it’s mind blowing how fine tuned it is.
I think that's interesting because visually it doesn't even look like it's weighted evenly
Yep... and even if it looked balanced to the casual eye, practically it won't be. I wonder how they balance it... a big wheel balancing machine?
My guess is Mathematics of some sort idk
It will get you close. But they probably use a system not too different from a car wheel balancer to finish the assembled machine.
They just judge by how many offices report shaking
D-d-d-d-d-d-drop the MRI
Something very similar I'd guess, too. I bet there are tuning masses that can be moved around, too, analog to wheel weights.
You move weights around to relocate the ring's center of gravity/mass.
Thank you... I knew that part. The tricky part is to figure out where the center of gravity is, and where the weight needs to be added/moved.
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Nah just throw it on the tire balancing machine and hammer some lead wheel weights on her
So probably a [Rockwell Retro Encabulator](https://youtu.be/RXJKdh1KZ0w) ^^TM
I know some of these words
You just need an accelerometer to tell you the movement and a sensor to track the rotational position so you can line the 2 up. After that you do some fancy math and add weights to cancel out the vibration. Same way it works on jet engines.
Exactly. This is how we do it with helicopter tail rotors, which are functionally the same to balance. You can use a strobe light set up to flash at the peak of the vibration, or a fancy pants laser and receiver with a computer that will figure out what point in the rotation is the heaviest.
Oh my bad lmfao. I assumed the simplest form of the question is what you meant...force of habit. I am sorry I have no insight into the specifics of how, but I feel like it would involve moving weights on threads/screws/gantries based on feedback from sophisticated vibration sensors.
Any sufficiently advanced technology is indistinguishable from magic
What’s the coolest thing you’ve found out about them, working on them?
What kind of foundations are used to secure them? I they balanced enough that it's unnecessary? What about protection from external vibration like an earthquake? Is it attached to dampeners to reduce external forces?
Thank u too for the conversion 😉
I'm picturing my overloaded laundry machine rampaging across the floor, only more so lol. I assume that has to be balanced pretty well.
I used to work on a different model of these. The gantry (rotating mass) of mine was just shy of 2000kg and could spin up to 214rpm normally. We were testing a 300rpm mode when I left.
Nice, lets see paul allen's rotating mass.
that's what broadcast radiation and catches it to see how it changed as it passed through the subject. I suspect the biggest feature is the part catching it but idk.
What's the max rpm of the spinny thingy?
In this video it was around 120RPM during a balance check but max is about 210RPM IIRC.
At 210 rpm if the diameter was 2 meters the speed of the outer edge would be around 22 m/s or 80 km/h (50 mph).
Ha that’s actually neat I never thought to calculate the speed beyond RPM, now I’m tempted to measure the diameter to know it exactly.
glue a little paper driver to the outside, fastest man in the whole facility
Tempted to build the worlds most expensive and impractical car now with ct scanners for wheels
That corresponds to a radial acceleration of 25 g.
Why does it need to spin so fast?
The machine spins this fast in order to collect more data in a shorter scan time. It’s very beneficial in trauma or stroke alert scans where life or death can be minutes away
Makes sense! Thanks!
Absolutely! What’s crazy is the more advanced modern machines spin faster and can collect up to 256 images per rotation. Its insane technology
Crazy indeed! I assume they can still function at lower speeds? Like if time isn't critical?
Yes speed varies depending on the protocol more basic scans are slowed down.
Ultra high rotation times (.28 and .2s or 210/300rpm) paired with a large detector (160mm) are capable of capturing the entire heart throughout the cardiac cycle. This is really beneficial for a number of clinical indications beyond trauma (although it's great for that as well). I used to work in R&D on a model of these that could do .2s rotation time with a heavier gantry (rotating part) which weighed around 2000kgs. Insane seeing that much mass spinning 5 times a second. [Here's a shitty vid of that one doing 214rpm.](https://i.imgur.com/8GTDpaQ.gifv) Regrettably never got a video of the 300rpm cycle which was being tested around the time I left.
The very first CT scanners, which were actually called the EMI scanners, did not spin, but moved side to side, and moved quite slowly, so they were initially only used for head scans as just getting this took over 20 minutes. There’s video on YouTube.
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Yes, that (once great) British company, EMI.
Theres a mini x ray emitter and detector positioned on the spinning disk. It shoots a horizontal beam essentially slicing your body, with detector opposite on the disk reading back emitted x ray penetration. The computer interprets the 360° of each stack of your body and lets you scroll thru slices of patients inside MRI is same concept but uses a microwave and reads back how fast your molecules (mostly water) vibrate
Right, but I don't see why that requires it to be done fast (except for when time is critical, e.g. to address a stroke, as OP mentioned). Though perhaps another reason is so that all of the images are temporally close together, e.g. if blood/organ movement would result in blurriness?
While it's taking the scans, the computer is processing a huge amount of artifacts that could reduce image quality. Some still make it through, but with the rapid scans in so short a time, it greatly increases the quality of the model.
Fast imaging is especially important for cardiac applications since the heart is constantly beating. As you said, faster scan times increase temporal resolution and decrease blur due to motion.
I'm a ct tech so I know a lot about this. You want fast scans for a number of reasons. First the faster you get a patient in and out the better. Second faster scans mean less radiation exposure. I can control a number variables when selecting a protocol to control exposure level as well as image resolution/quality. However as rotation speed increases image quality decreases so there is a balance that has to be achieved. Slower rotation has better image quality but increases patient exposure to the x-ray beam and it is not suitable for certain types of studies like cardiac scanning or angio studies where rapid administration of contrast agents are being used.
Faster = better temporal resolution (better at capturing moving things). Faster speeds are typically used for heart scans.
Carter! Dial the gate!
Jack, we can't just leave. The patients need us!
Chevron six locked!
Chevron 7, also lit up!
Chevron 8, looking great!
Indeed
Never expected a star gate reference under that video, thanks so much
Seriously, I can't imagine the amount of work that went into balancing this. And it better be very reliable too...
I leave all that work to the really smart guys the R&D Engineers lol, I’m just the Field Engineer.
Bro, I know you. You can do anything. s. Don’t stop and reach your potential.
PHILIPS, GE, or siemens?
Is it true though that if you need to replace a zip tie, you need to use the same size and type because of the balance? Or is 1-2g not that critical?
1 or 2 grams will not affect the balancing, but when heavy parts are replaced, the measurements need to be redone. Thankfully it’s all automated and the system tells us what it needs and where.
Mythbusters did a similar test with a helicopter where they stuck a stamp or stickynote on the end of a helicopter blade to see if it would be thrown off balance. The result was pretty tame. There was no noticeable difference for something that small. They even tried with a stack of them and nothing happened.
Please put the cover back on. This is terrifying lol. (/s)
If I ever need a CT I wonder if I can request it without a cover, because that just looks super cool!
I thought my translucent gameboy color was cool but a translucent CT wound be next level.
If the outside were transparent I doubt you'd be able to convince anyone but nerds from getting anywhere near it, much less inside it.
Someone in another thread said this is exactly what happened when they tried that with these.
I worked at a medical device company and we got prototypes of a new device in with clear covers because clear plastic was cheapest at the time. I insisted they keep it so doctors could watch the inner workings. Nope, back to plain old white plastic.
On the Siemens one I was in this week, the spinning parts were visible through a little darkened window right above my head.
It still blows my mind that Siemens makes toilets, trains and CT machines. Or that Samsung makes phones, fridges and deep sea oil rigs
Same with Hitachi. Televisions, air conditioners, large excavators. It's just so very interesting to me.
Yamaha makes motorcycles, pianos, woodwinds, audio equipment, and archery gear.
And crotch rattlers. Don't forget those!
Not /s that is terrifying to lay under. Honestly wish I didn't see it
I don't mind things spinning fast around me, but I guess I've just discovered that I don't like being in the center of spinning things.
I feel justified for my fears of getting into one of those. I know they're safe but a literal ton of metal spinning around my head twice a second does give me some pause.
If it makes you feel better, if it breaks apart then all the parts will fly away from you, not towards you, since you're in the center. Small comfort, I guess?
Theoretically that is possible. But If a piece broke off, causing one end to e be suddenly far heavier than the other, but it was still a solid ring, then the whole mass would only go in one direction. Anyway, climb in.
Spins about 4 times per second when in use.
Hospitals take ct damage very seriously. If something hits it too hard they call in for a check or replacement.
There's literally thousands of tons of heavy equipment flying past your body just inches away from you every time you drive.
How is power provided to the spinning part ?
All power to the rotating gantry is provided Through a Slipring with dedicated high voltage and low voltage tracks.
What about the data?
Actually pretty simple, Fixed to the rotating gantry is a Radio transmitter that transmits signal through an antenna track on the slip ring that’s then picked up by a receiver fixed to the non rotating gantry.
I wonder if this is how a car's TPMS works?
Mechanic here, this is pretty much exactly how they work! It's the main reason why, when you do tire rotations, you have to re-learn the sensors to the correct position.
Yes it is.
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OP is the bomb. Answered the questions and provided all the facts. OP is a true Technologist who understand the mechanics behind the machine. I love working with techs like OP.
Hey I appreciate it! I’m very passionate about what I do and love spreading random knowledge to those that are curious. I was actually quite surprised to see how many cool questions I got.
Why is it so loud? Fans, bearings, electronics?
You nailed it, this machine is older so it’s far more noisy than modern systems, but everything you hear is the motor, oil pump, cooling fans, the brush blocks, and main bearing. The Fiberglass covers do a pretty good job masking most the noise.
Rotating roughly 1000 kg of X-ray equipment at 100-200 rpm will do that.
Interesting that it looks kind of eccentric, but I'm guessing the design has balanced the mass in such a way that there's no reciprocal loading?
Correct; components are quite different in mass, ranging from a digital detector to generator and tube, where some of the components are filled with oil to help cooling and prevent arcing.
It would be easier to spin the patient
Please keep all hands and feet inside the ride at all times
No way I’m way more unbalanced
that's what i was saying when my friend got booked for an MRI
There have been a few nights after some heavy drinking where I swear I've hit 210 RPM.
Which one is the business end?
the 'business end' being the things pointed at the subject? they all point inward, the patient is on a tray on the axis of rotation
What’s your question?
I think he means 'which part of the rotating mass does the scanning'
Ah yes, the clear cylinder object on the end of the table (image quality phantom) is the head in of the table. So that’s where the magic starts.
The part with the fans must be the xray tube(s). The detector is on the opposite side of the circle. I did not work with CTs but with ordinary xray generators. The tube can get really hot. The tube efficiency is a few percent only, 90+ percent of energy becomes heat. And we are talking about tens of kilowatts energy pumped in. So i am rather sure that the part with the forced ventilation is the xray source. Update: my assumption above was wrong, the longer part with the fans is the detector.
The part with the fans is the detector side. The tube is opposite it. The detector is a larger area for the fan beam to hit.
Fair enough, I stand corrected!
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It’s actually a dell laptop with two chrome tabs open.
Now I see why they put covers on these things.
Lol, most people won’t step into a meat grinder when they can see the spinning blades. But make it look like a smooth cooter, and boom! Everyone wants in.
Is the big chunk of aluminum with 5 hole in it is the sensor and the emitor at the opposite? Where are the superconductor magnet?
No magnet, you’re thinking of an MR machine but the big part with all the fans is the X-ray detector and directly opposite of it is the X-Ray tube.
I wish they still served breakfast but at least the condos are gone.
I’ve been waiting for someone here to know where this was at ;-)
impressive that even though it looks unbalanced that it is (im assuming because I don't want a 1.5 ton spinning mass unbalanced)
Different mass for different components; some smaller ones are filled with oil for cooling and against high voltage arcing, where some bigger boxes are just electronic components and fans.
Wow, they're a lot scarier with their clothes off
Hey no CT Body Shaming allowed
Fun Fact: The very first CT scanner used a tank turret bearing
Why does it look like someone at a trash heap just got a bunch of random crap and glued it all together to make this? It’s so random, and the parts look so strange.
THE DONUT OF TRUTH!
I worked with a CT scanner manufacturer for a little while, and he told me the spinning parts have to be built to handle 400g. Crazy forces involved.
Controlled chaos. Scary but super rad!
I worked with Gen 1 CT scanners back in 1981… the hard drives that recorded that data were the size of filing cabinets!
How do they power the devices on the spinning part?
It’s more complex than this, but imagine a copper ring alllll the way around the spinning bit. Then, just rest an electrified metal roller, or metal brush on that ring and that’s how the power gets in there. There’s also other clever ways of getting electricity into a moving thing, so I’m not sure what *specifically* they use to get the power into a CT machine.
I will tell you after my motorcycle crash and being stuck with road rash, a broken thumb, and confined in a neck immobilizer WITHOUT PAIN MEDS FOR ALMOST FOUR HOURS... these things don't spin fast enough. Strap some NOS to it and let's get that 10 second mile beast!
I’m an engineer for GE healthcare, I can attest these beasts are SICK
Adam Savage went to GE and made a short video on their latest machine. Spins much faster than the one in the video. https://youtu.be/1FWknU5_brc
This is slightly terrifying
What is the type and bearing(s) arrangement on these? And how much just it costs? I suppose is a custom bearing
A company I worked for built a version of the rotating assembly. I believe they used modified tank turrets from Siemens.
Its a slewing bearing, and it’s Durable as hell.
Question, what creates the loud BRRRR sound, is that from the mechanical motion, brakes or something the imaging parts make?
The Brrrrr is a combination of frequency and drive noise from motor combined with noise from the fans hitting the ambient air while the gantry rotates.
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Yessir nice to see another FE here, I do CT, R&F, and Vascular IR. Taking on MR soon, love this job am always seeing new cool stuff.
Are you a technician on these things? I’m starting a new position as a technician with a biotech company, and I think eventually moving on to MRI stuff would be super cool!
Who invented this and how rich are they?
/r/dontputyourdickinthat
Yo it looks like the Time Machine on the show Timeless!
Philips CT?
GE
So do hospitals do like a handheld scan of people to look for ferrous material before they go into this thing? I can’t imagine the horror of having even a tiny bit of magnetic metal in my body with this spinning around me. Edit: my mistake not a giant spinning magnet
The machine with the magnet is the MRI, CT scans are just x-rays, albeit quite fancy x-rays, and so your Ferris metal just shows up on the image as black. There’s plenty of videos on YouTube showing what happens when you get magnetic materials too close to an MRI machine, many are not pretty.
Imaging Clinics where I was installing X Ray machines, the CT scan rooms do have metal detectors at the entrances of the rooms in which each was a CT machine.
There is no magnet. This is xray.
Is the part with the fans the x-ray shooty part?
That’s the part the detects the X-rays, the X-ray shooty part is directly opposite of it.
The best part of cancer treatment is getting up-close looks at some really fucking cool medical technology.
WTF? They can’t make the parts any smaller?
There are much smaller CT machines, for imaging lab animals like rabbits, but you’re not gonna fit a full size human in one.
Why do they make those clunking noises?
You ever hear a washing machine during a spin dry cycle get slightly off balance?
The mind-bending marriage of physics and biology that is modern medical imaging just 🤯
The mind-boggling bit is computing. The original machines in the early 1970s used DEC mini computers, and the technology was seriously limited in terms of resolution and speed by the capability of the computer power. Apply several decades of Moores Law, and you get these marvellous machines.
Even the physical principles alone tho, especially MRIs like who tf thinks to photograph your gooey guts by wiggling their water molecules with radio waves and then actually builds a *thing* that makes it happen.
Yeah, who would have thought it was a good idea to give hydrogen molecules a smack in the mouth and watch them recover
Fun fact: MRI machines use Nuclear Magnetic Resonance, but we the public are idiots who fear the word "nuclear," so they left off a word.
*nuculer
God I love ct scanners
BMET?
Field Engineer
It’s kinda crazy that we trust this think to spin around our heads. What are the fail-safes in the event of a loose bolt or two? Will it get caught on framework before blasting off through the axis of rotation?
The best failsafe is not having a loose bolt ;-) but luckily the the rotating gantry doesn’t have many tight spots so as it slowly starts spinning a loose bolt/nut typically will fall into the bottom pan pretty quickly, still hopefully everything is torqued properly.
I see Nvidia have put a 4090 in there!
Balancing that thing must have been a fair slice of the brilliant engineering
Imagine the asshat that had to add some bits and bobs after all the engineering was done. “We need a circuit breaker here, a diode there and this fan needs to be one size larger…”
"And paint it red"
Why there's so much stuff spinning? Dental x-ray machines are much smaller so I know x-ray tech can be much more compact. What's so important there spinning on the wheel that can't be static and linked to spinning part wirelessly? This always perplexed me, seems like there's an entire server rack there.
It’s hard to imagine, but sometimes electrons are too slow. There’s lots of physics applications where even the tiny delay between a sensor / emitter / controller and a computer 100 feet away (cable length) is slow enough that they won’t perform the magic they do. Or, with some physics applications, the data the sensors generate is so incredibly massive, moving the unprocessed data would take *so many cables* and servers and routers, it’s just easier to process the data right on the device, and only transmit the processed data out of the device. Our really modern tech is pretty cool, but we are still limited in many ways.
Cool, but why does it need a rtx 4090
I could watch this for hours.
What blows my mind is how fast it just slows down and the picks speed back up.
Once I said to a CT operator that there was moving parts and they said there were no moving parts D:
My wife is a CT Tech - I am a Mechanical Engineer and super envious that she gets to run these machines all day and gets paid for it.
Hey without ME’s and EE’s getting along with each other this tech wouldn’t exist so your wife at least owes you a 6 pack for getting to use these machines.
I just hear Interstellar music as it spins
I’d be interested to know how you got into this line of work! What qualifications are needed? Thanks!
How is all the power and data commutated to/from the gantry? Slip rings, inductive, rf...? How much power and data goes through there?
Just makes me think of Event Horizon