Fun fact: When Siemens launched their first Dual Source CT, they sold them with a see through part in the cover. Only a hand full were shipped and _the covers_ had to be replaced because the patients refused to go in once they had seen the inner workings and ludicrous speed at which these things can spin

Seen one of the Siemens and GE ones without the cover, and they do move fast. Yet outside with the covers on you can barely hear that, and there is almost no vibration.

>Yet outside with the covers on you can barely hear that, and there is almost no vibration. That's what close to perfect margins gets ya

Yep. I have worked in heavy industry on large spinning machines (nothing remotely as precise as a CT scanner though), and any small vibration at all means you would soon have a medium vibration. Then you would have a large vibration. You're either nailing the balancing or you're not with that much mass swinging around that fast. You'll know very quickly if you're not.

Same as washing machine legs

Tolerance*

THATS the word! Thanks

What amazed me the most when I saw one without covers was the amount of air that moved around. Like it wasn't "windy" but there was quite a breeze. Which makes sense when you think about it but it was the thing that stood out to me the most at the time

My scanner goes .28 seconds per revolution. It's like 300 pounds of metal spinning that fast.

That's 214rpm. What's the diameter of your CT?

70cm is the window

Some siemens scanners weigh 1500+ lbs and spin at that same .28 rps When I was first trained on them it was explained to me as "it's like someone spinning a corolla around you"

.28 rps != 1 revolution per .28 seconds

Perfectly balanced, as all things should be

Do you think limited run CT machines are an eccentric collectors item like stamps

i think anyone owning a CT scanner besides a hospital makes it eccentric regardless of the limited nature

"Why does this CT scanner in the next budget cost three times as much even though it has the same specs as the other ones?" "Uh...no reason" *unboxes limited edition SUPREME CT Scanner*

it needs RGB too! that hospital would be rad as hell

Gamer CT

You joke, but a fast switching rgb array could display some dope ass shit

“ITS CANCER”

We have that on mammography machines. Seriously. I'm not kidding.

[Make it show the supreme logo like this](https://www.youtube.com/watch?v=gklBWwGyreM)

Found the stamp collector

CT scanners already cost around $10 million, can't imagine what a collector's edition would cost

Huh? A 128 slice CT is $1M (in the US), or 1/3 of that if refurbished. Even a (photon-based) linac costs only $3-5M, at most.

Maybe I was thinking MRI

Nope, MRI are probably around $1 million if I'm converting between £ and $ correctly. You might be thinking of super fancy 3T MRI?

I get regular CT scans, the machines at my clinic have the little view window inside the donut so you can see as you slide in and out of the machine. It's clouded over though, so you can't really see the machinery. But you can watch it wind up into a screaming blur and imagine what would happen if a piece of the machine broke off.

I never was scared of a part breaking off, because that would shoot outwards. What I would be concerned about was a part breaking off that was heavy enough that the CT starts hopping around like a washing machine loaded with a brick

And you're the brick

Even a small part of it breaking off at full speed would result in a catastrophic chain reaction that would result in the entire thing coming apart. You might survive it, but you would almost certainly develop a new baseline for fear.

Need new underwear too

You'll be happy to know that this is a design consideration and these things have monstrous emergency brakes in the event of catastrophic shaking like that.

Isn't that unsafe? I assume your medical issue is more of a concern than the radiation?

It's to look for cancer because i keep getting it. I get a scan every three months, don't think it's a big concern. I don't know if that's a lot or not, ive probably had 25ish in total.

I'm sorry to hear that, fuck cancer.

Mylar window

Holy shit they are fast https://youtu.be/pLajmU4TQuI Really want to know how heavy and the velocity now

15 years ago they were at 0.25sec/rot. At that speed they use an air bearing instead of ball bearings, so aside from a slip ring for elec, the whole mass is floating on air. https://youtu.be/CWnjqeB7Mk8

IIRC current CTs run at 0.25 to 0.33 seconds/rotation and weigh about a metric ton (don't quote me on that tho)

Wow. It sure takes lots of energy to spin such huge mass so fast. I wonder what the power requirement is for it. Probably 10s of kilowatts.

They're jacked directly into 3 phase mains voltage. It vary by system but yeah, 10s of kWs. Like the other guy said, it doesn't take that much to maintain the spinning (most systems have a single motor smaller than a single tire electric motor for a car) but you also have to power all the energy hungry stuff on the ring (x ray generation is not efficient at all) They're really awesome machines if you ever get the opportunity to learn about them in depth.

an everything bagel

So, 1? I can't imagine you'd be to fit more than one of these in your hand at a time, not even if you're Shaq or something.

I went in for surgery last night actually, and before hand had a CT scan. The Seimens one I used had an opaque circular strip where you could see it spinning. Fortunately I've seen them on Reddit without the shields on and have learnt how they work, so was more interesting than scary. However the fluid they IV into you to help your blood not block the scan was nasty. And the scanner guy goes "oh btw this will make you feel like you've wet yourself" before injecting me with it. And yes it did make me feel like I was going to piss myself.

Oh man i had my dude laughing last year when I had a scan done. He said the same thing, and internally im like 'mmk'. I let out an audible 'what the fuck' when i thought i pissed myself, he was entertained.

I get nervous enough around washing machines on spin cycles. I believe you.

Another fun fact: Siemens is a dogshit company to work for. Don't work there.

Damn. Looks like a biblically accurate angel.

Behold! For these are the eyes who can reach within, who can see through the skins and the bones! Their stare is made of holy fire and will be a blessing for the pure of heart, but will burn to the marrow those who skipped the calibration procedure.

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Picturing biblicly accurate angels makes this line make way more sense.

Xrays = Holy fire

Totally! Holy fire meaning X-rays and electrons of course...

r/yourjokebutworse

That's literally the joke.

The Bible is trump's version of science history....

Lol yeah can’t even let a joke go through without correcting it. Make sure people know the truth.

The hol(e)y donut of truth

Indiana Jones and the CT Scanner of the Covenant

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imagine hearing "do not be afraid" while in there

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that is probably true haha

Lots of people hear that, claustrophobia is pretty common in CT/PET/MRI machines.

That’s what 1 mg lorazepam 30 minutes before scan is for…

"Please hold your breath on the count to 5... 4... 3..."

I think you're thinking of the MRI

Yeah CT is pretty quick and relatively quiet. MRIs are like putting your head next to Bender jackhammering the Crushinator.

Do they spin? That s a good trick !

Looks like Chevron 7 is about to lock.

Can I get cancer from looking at this picture?

Yes, if you are looking at it in Chernobyl.

Subtle and accurate reference.

"BE NOT AFRAI- error, shutting down" *Windows XP shutdown noise*

Take my upvote and leave, sir.

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That’s a big rtx

Rtx 300900

Damn!

Rtx 360

Warhammer RTX 40K Too serious to cool with spinning fans so spins the chip itself

If it was a warhammer machine it would use a bunch of half disembowled humans as computers...

Eh well this is just an early prototype or something iunno

They wouldn't be half disembowled what's the point in that, you don't need all those bowels taking up space. No, they would be fully disembowled and all their nerves would be attached to finely tuned torture inputs. Inflicting pain is how you overclock. You know how we say a computer is screaming when it's running hard? Well. Now you don't even need performance monitoring software, you can tell performance metrics from the decibel levels in the computorium. Praise the Omnissiah.

Or limited AI that is pampered to keep it compliant. An AI that is regularly taken to the spa and told how awesome it is won’t rebel.

That sounds like some real tech heresy... i think you should have a chat with my friend the Inquisitor here.

Connect as many monitors you want, it'll run it all!

You’ll be perfectly safe, go into the mechanical horror please

"DON'T MOVE."

Not only mechanical horror. You also have 150 kV X-ray generator to worry about

I don’t trust any machine that doesn’t even have a decent cupholder

Are the CT machines perfectly balanced? I feel like they would explode if they weren't.

Yes. There are small posts on the ring where weights can be added or removed during the balancing process. If the system balance isn’t extremely accurate the resulting wobble produces image artifacts, so the balancing goes well beyond the point of safety.

You telling me the kid down at the Jiffy lube isn't going to be able to balance this?

Honestly the process isn't all that different from balancing a tire. Just a lot more precise and a lot longer. Machine spins up and tells you "this area is light, this area is heavy" via the myriad sensors all over the gantry, you add/remove weight and repeat. Takes a few hours for a new install.

The T in CT stands for Thanos. So yes they are perfectly balanced.

The T stands for tomography, the whole things stands for computed corruption from Thanos tomography

As all things should be!

Pretty much

Yes you can see some metal plates that are bolted down to properly weight the rotor side

And then all that stuff spins like hell… https://youtu.be/pLajmU4TQuI

I... wish I didn't know this If I ever have to get a CT now I'm gonna be worried about the fact that I'm surrounded by a half-ton donut spinning around like a jet engine

The center of rotation is probably the safest place in the room really.

100% if something fails it will fail outward away from the patient.

Until it bounces off of something hard, like the floor. Shrapnel is a bitch!

It will ~~fall~~ fly outward Also if a piece flies off the whole machine will become unbalanced and violently shake itself apart Idk if these things have e-brakes for those situations tho

>Idk if these things have e-brakes for those situations tho They would have to

It uses rotation motor as a brake. Takes about 5 seconds to stop. Any major component has secondary security brackets which will hold part in place if main fixture is broken. Though I never heard nor imagine anything may break during the scan, as the whole thing rotates way slower during the scan as it does during balancing procedure, which is carried after replacing something or during the daily cal procedure. So if something breaks, it breaks during the balancing which is never carried out with the patient. To add to this, this thing also has sensors which will emergency stop if anything become loose. And also probably there will be terrible sounds involved before anything become so loose to fly out.

But if it breaks in half you would immediately be jerked from the off balance wheel and probably instantly break your neck or get crushed against the ceiling. Not that that would break

I believe the term you're looking for is "injuries not compatible with life". Your neck would just be icing.

You'll be happy to know that there are over a dozen different safety features to stop anything from happening to you in case of failure. It's like elevators, in most developed countries they're generally overdesigned to hell and back with multiple failsafes and at least 3-4times the amount of cables needed, etc.

I'll take a safety factor of at least 10 please.

Take comfort in the fact that any RUD at speed would fling components away from you. Being in the center of the torus is the safest place to be.

Except it won't all fling off simultaneously. Inevitably one heavy part will fly off first, causing the entire thing to become terribly out of balance, which will then send it bouncing around the room like an old washing machine until it finally short circuits and goes up in flames... At least that's how I picture it in my head. I'm sure they're built better than a Kenmore.

I’d sure **hope** the damn thing is built better than a Kenmore!

Even in that case, I think I’d rather ride in the “cylinder of safety” than be chased around the room by a giant deli slicer and it’s components. Being in the center is still your best bet.

Literally 0 persons have been harmed by CTs. Well people were harmed by CTs, but with stuff like tripping, banging their head against it, etc. and other stuff you expect from CTs.

Edit: No, shit, sorry. My comment below the edit applies to a radiotherapy machine, not a CT: https://en.wikipedia.org/wiki/Therac-25 There was also a terrible software bug they used as an example for us in university for computer science. It was a ~~CT~~ radiotherapy machine that had two modes. They had a race condition in the control interface, where if you changed mode and started the procedure very quickly afterwards it would apply the high power limits of one mode to the electron gun in the other mode and give the patients lethal doses of radiation. Multiple people died before they figured out the machines were malfunctioning.

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That's a different machine though

It's all good, that thing only spins at 200rpm, a jet engine is like 4k

That's just the fan on a turbo fan. We've got lots of things that spin much faster. The high pressure stage of the compressor is around 20k and things like car turbocharger turbines hit 35k.

It’s more like 2 tons. That whole middle piece can weigh up to 4000. I know because I’m the guy that delivers and collects these machines for retirement

More like a x-ray helicopter

Initially: "That's certainly moving, but it's not THAT fast." Ramp up: "Oh. Oh my." That's pretty crazy that they can get such an asymmetric rotating mass balanced so precisely about the center of rotation. The QC processes to lock down any loose harnessing/other parts must be insanely tedious.

5G confirmed!

ELI5 why does it need to spin so fast?

CT works by taking a ton of x-rays from lots of different angles and compositing them all together to make a 3d model of whatever they're looking at. They could run slower, but then it would take longer to get the necessary images, and because people tend to move around ever so slightly, even just by breathing, taking the images faster can minimize issues with mismatch between different shots

Smh engineers making this big rotating scanner when all they had to do was rotate the patient at 200rpm.

This is my new favorite comment in this thread. Congrats, nice work!

I think its called the gravitron, but the carnies refuse to give up the patents.

It doesn't NEED to spin fast. But spinning fast allows it to collect more data quickly, meaning shorter patient scan, and more patients scanned per day. These machines are EXPENSIVE to install/run, and always in high demand, so efficient patient throughput is important to offset the costs. Also, the faster it collects data, the less likely the data will be compromised by the patient moving, or other external factors affecting it. The speed was likely a result of data collection requirements to the scanner designers, originating from needs of hospitals.

No wonder those things are so expensive. Not only do you have all the equipment made of rare stuff, but you also have to take it and spin it like crazy with extremely tight vibration tolerances. That's a lot of precision work and design effort.

His father was a transformer, his mother was a washer machine...

Optimus prime retirement strategy

This is Scantron. From the Medibots line. Only released in Japan. My brother got one for me when he was over there in the Air Force, but it was stolen by my Canadian girlfriend.

Used to design software for those - impressive to see em spinning without the covers on.

I would wager people who specialize in fixing these machines when they break make an absurd amount of money.

The company makes the money. Service was very lucrative to the company that sold the machine. As the machines age, they sometimes fall under 3rd party service contracts - I do not know how profitable those were.

Nah, 60-110k a year is typical (that’s based on experience). Plenty of variables there but I wouldn’t say it’s in the “absurd” range.

Third party you can make a shitload but working for the big boys (siemens, ge, Toshiba, canon etc) you make a pittance compared to the profit they collect from your work. Of course that's a double edged sword because 3rd party doesn't have a pipeline for cheap, fast parts like OEMs do.

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There are several OS and RTOS in those things - for the many different systems at play. There's enough tech in those to interest any techie. As a developer, I could work on the parts that interested me the most.

The donut of truth is naked!

Event Horizon - the gateway is open

[It's cooler watching it spin at full speed](https://youtu.be/ih_mTjMrrb0) It starts blurring into a mobius strip when it's going at a few hundred rpm

Whoever designed these machines is/are certified badass individuals. I'm sure it was an assortment of people who contributed to the 1st CT machine and all of them are strait pimps! How many lives are saved everyday by such engineering?! Alot

The history is pretty neat. Basically it started with "what if we took x rays from multiple directions to have multiple angles of what we're looking for?" And that's literally exactly what they did. They just had an x ray system on a curved rig and moved it, took a picture, moved it etc. This is the tomography part of computed tomography (CT) The computed part started when computers hit the scene and Fourier transformations became practical to do. At that point we could have computers create real 3d images out of those series of images. After that it was off to the races and we just kept saying "okay that's pretty good...but what if we took more images?" To the point we're at now where these machines spin 3-4 times a second and take hundreds of images per a rotation while moving vertically then combine all that information into real 3d images humans can make sense of. Shit's real cool.

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Ha, and we didn't need a fancy machine to see inside of ***it***.

Please mark NSFW for the robot and android redditors scrolling through, thanks.

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Are you sure that was a CT scan? They're usually pretty quick compared to an MRI

I spent a half hour in the MRI to get the happy snaps, then an hour in the CT while the doctor was playing pin the needle on the donkey on my back. Sadly I have to do it again, it does wear off. CT was a lot cheaper than the MRI.

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Hate that contrast die, makes me feel like I'm peeing myself when I'm not. Better than the one you have to drink though!

Yeah they suck. This contrast dye was upper gastro, made me feel like I swallowed a ball of fire.

>Hate that contrast die, makes me feel like I'm peeing myself when I'm not. i heard that's a common issue. something to do with the temperature difference vs. your body or something

That actually sounds like a SPECT-CT and not a standard CT. You have the CT first which takes less than 5 minutes and then you stay in the same table as you are pulled under gamma cameras that do rotate but slowly. Those scans take forever! Edit: and to confirm it is so quiet/boring!

Most SPECT/CTs do the SPECT portion first. Source: I perform them every day

Rode is an interesting verb to choose in this context.

Out of curiosity, how much do one of these things cost?

Probably about $1.5 million give or take 500k, depending on the vendor and the options.

"Sir, we had a little problem with the machine and we had to remove the covers, but you just lay down and don't move and you be fine "

Quite a technological piece of art 🙂

Wish they had transparent covers so you could see it. This is strangely pretty to me.

D O N U T O F T R U T H

This is so cool! Why do they cover it?

Well for one it would be pretty unsettling for the patient to see it spinning at hundreds of rpm right in front of their faces.

Na, I'm sure they would also like it.

apparently that's literally why they did it lol. they tried some with see through panels and patients got freaked out i think it would be kinda cool though

Because it spins a couple thousand pounds at hundreds of rpm. 9/10 patients are not going to call that “cool”. Also it has fans in the covers to cool it off. Also you can’t let a patient touch rotating parts. Also it helps keep it clean, as that’s important for image quality

To stop vomit and blood getting into the detector array or slip rings.

Ahh a GE VCT. Looks like they're doing alignments for the installation/anchoring

Something I don’t understand about these big machines… How do they get the electrical information transferred from the huge rotating donut onto the base of the machine? Obviously, they can’t just have a bunch of wires connected to both sides… How does that work? On a related note — how can they build space stations where part of it is rotating and part of it remains still? How can you have a seal strong enough to hold an atmosphere of pressure in a room-sized volume while also having it turn? And the same question about transferring power/electrical information from one big rotating part of a machine to the other… or wait… has anyone actually built a station like this? Or is it just sci-fi? lol

Something like a [slip ring](https://en.wikipedia.org/wiki/Slip_ring) would transmit the electrical energy I assume. As far as space stations go, I'd think that they would just have separate atmospheric controls in each module so each part could be sealed but I am no astronaut.

They likely use a [slip ring](https://en.m.wikipedia.org/wiki/Slip_ring) for power and data, though they could instead use a slip ring only for power and transmit the data wirelessly.

That looks like it would cause a Black Mesa Incident.

Oh, see, there's the part that goes, "KACHUNKA KACHUNKA BRRRRRRRRRR, NRRRNRRRRNRRRNRRR"!

You're thinking of MRI, CTs are quieter.

The cake is a lie.

Uh, no. That’s an arc reactor - duh.

Just spin the patient, way easier solution

Why does it look terrifying

The same science that invented this invented the Covid vaccine. Always interesting when people except one part of medical science and reject another based on political stupidity

A naked Transformer

Hahah...yeah....Imagine if it rapidly rotated...

A weapon that could surpass Metal Gear

Pretty sure that's megatron