X-Ray CT Scanners From EBay, Brought Back To Life

If you have ever wondered what goes into repairing and refurbishing an X-ray Computed Tomography (CT) scanner, then don’t miss [Ahron Wayne]’s comprehensive project page on doing exactly that. He has two small GE Explore Locus SP machines, and it’s a fantastic look into just what goes into these machines.

CT scan of papyrus roll in a bamboo sheath.

These devices use a combination of X-rays and computer software to reconstruct an internal view of an object. To bring these machines back into service means not only getting the hardware to work correctly, but the software end (including calibration and error correcting) is just as important.

That means a lot of research, testing, and making do. For example, instead of an expensive calibration grid made from an array of tiny tungsten carbide beads, [Ahron] made do with a PCB laden with a grid of copper pads. The fab house might have scratched their heads a little on that one, but it worked just fine for his purposes and price was certainly right.

Scan of a foil Pokémon card.

Tools like these enable all kinds of weird and wonderful projects of their own. So what can one do with such a machine? CT scanning can spot fake AirPods or enable deeper reverse engineering than a regular workshop is normally able to do.

What else? Shown here is an old foil Pokémon card from an unopened package! (Update: the scan is not from a card in a sealed package, it is just a scanned foil card. Thanks to Ahron for clarifying.) [Ahron] coyly denies having a pet project of building a large enough dataset to try to identify cards without opening the packs. (Incidentally, if you just happen to have experience with supervised convolutional neural networks for pix2pix, he asks that you please reach out to him.)

The real power of CT scanning becomes more apparent if you take a look at the videos embedded below the page break. One is a scan of an acorn, [Ahron]’s first successful scan. Another is an interesting scan of a papyrus roll in a bamboo sheath. Both of the videos are embedded below.

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Hiring From A Makerspace Pays Off

A makerspace is a great place to use specialty tools that may be too expensive or large to own by oneself, but there are other perks that come with participation in that particular community. For example, all of the skills you’ve gained by using all that fancy equipment may make you employable in some very niche situations. [lukeiamyourfather] from the Dallas Makerspace recently found himself in just that situation, and was asked to image a two-million-year-old fossil.

The fossil was being placed into a CT machine for imaging, but was too thick to properly view. These things tend to be fragile, so he spent some time laser cutting an acrylic stand in order to image the fossil vertically instead of horizontally. Everything that wasn’t fossil had to be non-conductive for the CT machine, so lots of fishing line and foam was used as well. After the imaging was done, he was also asked to 3D print a model for a display in the museum.

This is all going on at the Perot Museum of Nature and Science if you happen to be in the Dallas area. It’s interesting to see these skills put to use out in the wild as well, especially for something as rare and fragile as studying an old fossil. Also, if you’d like to see if your local makerspace measures up to the Dallas makerspace, we featured a tour of it back in 2014, although they have probably made some updates since then.

DIY X-Ray Machine Becomes CT Scanner

Once you’ve built your own X-ray machine to take 2D images of the insides of stuff, there’s really only one logical next step: building your own computed tomography (CT) scanner to get 3D reconstructions instead. That’s exactly what [Fran Piernas] has done, and documented over on hackaday.io. While the original X-ray machine build dealt with scary hardware stuff such as high voltage and ionizing radiation, this time it’s the turn of scary mathematics like inverse radon transforms.

The original build, which we wrote about in December, uses a commercial dental X-ray tube and a home-made 65 kV power supply to send X-rays through objects. Transmitted X-rays are viewed using an intensifying screen that converts the rays to visible light. The result is a 2D image similar to that we’re all familiar with.

To create a 3D reconstruction of an object, you need a number of X-ray images taken from different angles. If you’ve ever been unlucky enough to need a medical CT scan, you’ll remember staying motionless in the tunnel while the X-ray apparatus rotated around you. In this build, [Fran] rotates the object instead, using a motor that may have once been part of a microwave oven (one of those “mystery motors” we all have laying around). The required sequence of images is simply obtained by recording video of the X-ray screen while the motor rotates the object.

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The Use And Abuse Of CT Scanners

David Mills is as a research scientist at the cutting edge of medical imaging. His work doesn’t involve the scanners you might find yourself being thrust into in a hospital should you be unfortunate enough to injure yourself. He’s working with a higher grade of equipment, he pushes the boundaries of the art with much smaller, very high resolution CT scanners for research at a university dental school.

He’s also a friend of Hackaday and we were excited for his talk on interesting uses for CT scanners at EMF Camp this summer. David takes us into that world with history of these tools, a few examples of teeth and bone scans, and then delves into some of the more unusual applications to which his very specialist equipment has been applied. Join me after the break as we cover the lesser known ways to put x-ray technology to work.

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LEGO Components Under X-Ray

[Nico71] works for a company that makes industrial CT scanners. These x-ray machines look inside a piece of equipment, allowing operators to verify assembly and to inspect for material integrity. It also allowed [Nico71] the opportunity to scan a LEGO servo he had lying around, and which no longer worked. The resulting images look fantastic, and really allow you to look into a closed system and pick apart how it works or why it’s not working. In this case, you can see one of the wires has been damaged.

[Nico71] plans to scan a bunch of LEGO components, comparing (for instance) official LEGO products with shanzhai knockoffs. Which is better constructed? It’s one thing to have thinner or cheaper plastic, or a lower grade of steel, but how is the part engineered?

We’ve covered a surprising amount of CT goodness on Hackaday, including this process for turning a CT scan into a 3D print and a post on improving a homebrew CT scanner. Continue reading “LEGO Components Under X-Ray”

Hackaday Prize Entry: A Better DIY CT Scanner

If you’re entering something in The Hackaday Prize this year, [Peter Jansen] is a guy you need to watch out for. Last year, he won 4th place with the Open Source Science Tricorder, and this year he’s entering a homebrew MRI machine. Both are incredible examples of what can be built with just enough tools to fit on a workbench, but even these builds don’t cover everything [Peter] has built. A few years ago, [Peter] built a desktop CT scanner. The CT scanner worked, but not very well; the machine takes nine hours to acquire a single slice of a bell pepper. At that rate, any vegetable or fruit would begin to decompose before a full scan could be completed.

This didn’t stop a deluge of emails from radiology professors and biomedical folk from hitting [Peter]’s inbox. There are a lot of people who are waiting for back alley CT scans, but the CT scanner, right now, just isn’t up to the task. The solution is iteration, and in the radiology department of hackaday.io, [Peter] is starting a new project: an improved desktop CT scanner.

The previous version of this CT scanner used a barium check source – the hottest radioisotope source that’s available without a license – and a photodiode detector found in the Radiation Watch to scan small objects. This source is not matched to the detector, there’s surely data buried below the noise floor, but somehow it works.

For this revision of a desktop CT scanner, [Peter] is looking at his options to improve scanning speed. He’s come up with three techniques that should allow him to take faster, higher resolution scans. The first is decreasing the scanning volume: the closer a detector is to the source, the higher the number of counts. The second is multiple detectors, followed up by better detectors than what’s found in the Radiation Watch.

The solution [Peter] came up with still uses the barium check source, but replaces the large photodiode with multiple PIN photodiodes. There will be a dozen or so sensors in the CT scanner, all based on a Maxim app note, and the mechanical design of this CT scanner greatly simplifies the build.

Compared to the Stargate-like confabulation of [Peter]’s first CT scanner, the new one is dead simple, and should be much faster, too. Whether those radiology professors and biomed folk will be heading out to [Dr. Jansen]’s back alley CT scan shop is another question entirely, but it’s still an amazing example of what can be done with a laser cutter and an order from Mouser.


The 2015 Hackaday Prize is sponsored by:

Hackaday Prize Entry: A $100 CT Scanner

What do you do when you’re dad’s a veterinarian, dumped an old x-ray machine in your garage, and you’re looking for an entry for The Hackaday Prize? Build a CT scanner, of course. At least that’s [movax]’s story.

[movax]’s dad included a few other goodies with the x-ray machine in the garage. There were film cassettes that included scintillators. By pointing a camera at these x-ray to visible light converting sheets, [movax] can take digital pictures with x-rays. From there, it’s just building a device to spin around an object and a lot – a lot – of math.

Interestinly, this is not the first time a DIY CT scanner has graced the pages of Hackaday. [Peter Jansen] built a machine from a radiation check source, a CMOS image sensor, and a beautiful arrangement of laser cut plywood. This did not use a proper x-ray tube; instead, [Peter] was using the strongest legally available check source (barium 133). The scan time for vegetables and fruit was still measured in days or hours, and he moved on to build an MRI machine.

With a real source of x-rays, [movax]’s machine will do much better than anything the barium-based build could muster, and with the right code and image analysis, this could be used as a real, useful CT scanner.


The 2015 Hackaday Prize is sponsored by: