CT Scans of various Mechanical Pencils

Yesterday I was able to meet up with a buddy of mine to try to get some CT scans of a few mechanical pencils. This particular CT scanner was pretty old, and only a 64 slice system, but it did have the latest software available to that model. Anyway, this thing is like magic when imaging the human body. The surgeon is able to select the particular part of the patient’s physiology that is being imaged, and separate it from the rest, and even view it in 3D (spin it around, etc). The first image below is an example of how this device works with soft tissues. It’s amazing what this system can do. It’s mostly image manipulation w/ software post scan. But to he honest this scanner is old as crap. Our newest 256 slice scanners make this one look amateurish.

Anyway, we tried for a few hours, but this system just isn’t made to look at mechanical pencils. I am happy with the results we got, but they are a bit washed out, over saturated, etc. We couldn’t do a “normal” scan – these are actually what they call “scout” scans – low intensity, low resolution scans. They are a pre-scan that they perform just to be sure everything is “OK” before the real scan.

I am working on a rig of sorts made from clear acrylic tube and rods that will allow us to capture a Kurutoga Dive under X-Ray Fluoroscopy. This will enable us to grab a video of what goes on inside while it is writing, spinning and advancing lead, etc.

Getting access to the 256 slice scanner could possibly happen when it is taken down for its next routine maintenance schedule. But the higher end imaging devices are in very high demand, so once it’s certified, if there are patients waiting, I’ll have to wait another 3 months for the next PM.

We may have better luck using a PET scanner, but that also is in very high demand.
I really want to get some videos of the Dive working. I’ll try to make that happen sometime soon if I can.


This is next level, never been done before, never been thought of before, never been attempted, borderline craycray, holy moly cool.


Mechanical Pencil Collector (MPC): Hey, I heard you have a CT scanner, right?

CT Scanner Guy (CTSG): Yeah, I do. It’s for medical diagnostics, though. Why?

MPC: Cool, cool. So, um, can I use it to scan my mechanical pencils?

CTSG: (laughs) Your what now?

MPC: My mechanical pencils. I collect them. It’s a thing.

CTSG: (still chuckling) You can’t be serious. You want to CT scan… pencils?

MPC: Absolutely! Each one has a unique inner mechanism. It’s fascinating. Like, there’s this one pencil, it has a gear system that…

CTSG: (interrupting) Wait, wait, wait. You’re telling me you collect mechanical pencils? How many do you even have?

MPC: Oh, just a modest collection of 347. Each one is a masterpiece of mechanical innovation.

CTSG: Three hundred and… (shakes head) And why on earth do you need to scan them?

MPC: To see the beauty inside! It’s like x-raying a Swiss watch to appreciate the craftsmanship.

CTSG: (sarcastically) Right, because everyone x-rays their watches.

MPC: Exactly! You get it. So, can I use your scanner?

CTSG: (pauses) You know what? Sure. Why not? Let’s CT scan your mechanical pencils. Who knows, maybe we’ll discover a new element – Pencilium.

MPC: (excitedly) Really? That’s awesome! You won’t regret this.

CTSG: (smirking) I’m already regretting it. But hey, at least it’s not another colonoscopy.

MPC: (beaming) This is going to be great. You’ll see, we’re going to make history!

CTSG: (laughing) Yeah, the history of the most bizarre CT scan ever.

(Both walk towards the CT scanner)

CTSG: (shaking head) Next thing you know, you’ll be asking to MRI your eraser collection.

MPC: (stops and turns) Wait, you can do that?

CTSG: (facepalms) I was joking…

(They both laugh as they enter the scanning room, the CT scanner ready for the most unusual session of its existence.)

MPC: (excitedly) Just wait until I show the scans at the next Mechanical Pencil Collectors’ Conference!

CTSG: (muttering) There’s a conference for that? What a world…


it was pretty close to that :laughing:


:exploding_head:whaat, the human body scan it’s amazing, the pencils looks from another world.


This is the post I would never have imagined in 2024, and at the same time, it’s the best post about mechanical pencils I’ve ever seen. Nothing represents curiosity more than that. Congratulations!!!

Didn’t you have any problems with the metals? Whenever I had a CT scan, they asked me not to have any metal with me.


Yes - the metal was causing all kinds of problems. We need to use a very lower power scan - but they are not made like that. On the newer scanners there is software that we could use to help compensate.



A kt dive video would really be next level. But how to operate it remotely inside the gantry?


I’m saying it now.

This is going to be the top topic for Q1 2024.



I’m working on that. I am thinking a clear acrylic tube to hold the Dive. A separate piece of acrylic would be mounted perpendicularly on a long arm and would have a piece of paper on it, and the whole thing would be resting against the lead tip of the pencil. It would be fixed so it could be moved back and forth - to simulate writing. The Dive would be stationary – the “paper” would move back and forth. A small cam at the end could cause the paper/arm to “drop” momentarily at the end of the motion, and then rise back up. Simulating the Dive rising and lowering, and advancing the KT engine.

Maybe something like that. It would be a test fixture that I could attach to the examination table. That way I could stand way back (still wearing lead apron) at a safer distance.
I’ll be working on a prototype. Once I get that figured out, I’ll be getting that video for us.



I’m here for the show


Interesting pics.

Is your friend a radiographer?

Just a few notes, I wouldn’t bother with anything metal for a full CT scan. Metal causes artifacts in CT scans that make the imaging borderline useless. Common examples are dental work and joint replacements. Anything non-metallic within the pencil that’s next to metal just looks like white starburst patterns. Perhaps newer software compensates for this, I’m not sure how well though.

Fluoroscopy would be interesting. You have the option of just suiting up in the lead aprons etc. The radiation dose is not really that significant unless you spend a lot of time with the machine. Interventional radiologists, cardiologists and endovascular surgeons spend their whole careers using fluoroscopy. Yes, they wear radiation monitors and yes, they don’t usually spend all day every day in the procedure suite, but you’ll only spend maybe an hour in there? I wouldn’t worry about the radiation from that, assuming you wear lead.

You might’ve only been joking about the MRI too. And we probably already all know this, but MRI scanners are just huge, powerful magnets. So don’t put anything that has any ferromagnetic components near it. You’ll also get artifact. Other metals are safe.

Needless to say, I’ve saved the pics that include any Clics.

Sorry if I’ve burst any bubbles.


Check this out for some info re: radiation.

Due to the inverse square law, doubling your distance from the X-ray tube reduces your dose by a factor of 4. Six feet away from the X-ray tube means 2.8% radiation dose.

Wear lead aprons and do a quick click and you’ve got your pics.

Disclaimer: I am not an X-ray tech and this is not medical advice. Do this at your own risk.


Dr. Dry :man_health_worker:


@dry you are correct. The radiation safety protocol calls for time, distance, and shielding.
It’s like a three legged stool. You could have all the distance and shielding in the world, but if you have a very long exposure time, you could still get yourself in trouble with higher doses.

I work for a healthcare system in the department that supports all these devices (Clinical Engineering). One of my buddies is an interventional radiologist, and the other one is the imaging engineer that actually repairs these devices. Between the two of them, they are just as excited as I am about getting the Dive video.

These are not actual CT scans. They are the scout scan that the technician would run before the actual scan. As you mentioned, the actual scan is too strong and causes a complete white out of all the metallic areas. The scout scan is a low resolution, low dosage, scan that just steps through the motions of the actual study. It’s like a pre-scan that the technician runs before they do the long one just to be sure everything is set up correctly. We are looking at maybe a PET scanner but it is hard to access because of patient demand.

I definitely would not recommend trying to get MRI scans of pencils. They will turn into projectiles in the MRI suite. FYI, the magnet is always on.
You do not want to find yourself in between a big hunk of metal and that magnet.


I’m betting that this will win the nerdiest thing of 2024. This is Nerd Infinitum level stuff. Great job Pdunc67!


The mention of MRI was in my made up story above.


Thanks for all the kind words everybody. In the interest of transparency, this is where I got the idea originally.

There is a very high-tech industrial CT scanner out there.
This is an article where they’re looking at the differences between counterfeit and legitimate earbuds.


BTW in the article, there’s a 3-D image of the AirPod scan that you can rotate 360. I was doing that the other day with an image of some dudes aorta. it was freaky.


Ahh yes. I remember seeing this.

I met with someone with Lumafield recently. Super cool company and tech.

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