Source Release — Open Source CT Alpha

openct-source

I’m very happy to announce the first release of the Open Source Computed Tomography (CT) scanner project. This is an early alpha release, and contains all of the source at the projects current stage, including the laser cutter design files for the machine structure, EAGLE source files, and the sample Arduino sketch.

The source is available for download here [zip], and is also available on GitHub. For potential contributors, the TODO file also includes near term project goals at a variety of skill levels, from adding end-stops and designing the official Arduino shield, to designing parallel detectors that decrease scan time, and developing a new source/detector pair for different wavelengths of interest.

I’m excited to see what folks do with this project, both now and as it matures. If you build one, want to contribute to the project, or encounter any issues, please send me a note.

In other news, the Bay Area Maker Faire is coming up in a short two months. With a good amount of progress on the Open Source CT Scanner, I’m going to switch gears for a while back to the Mark 5 Arducorder — I’d love to have the firmware and basic functionality working and demonstrable by then.

12 thoughts on “Source Release — Open Source CT Alpha

  1. First!
    http://imgur.com/nblFSfc

    I got the email notification about the files as I was sitting next to the laser cutter, so I was building it a few minutes after it was released 🙂

    Lovely design, Peter. Everything slipped together nicely, and it looks good.

    Being in Australia, I’m bereft of nice things like McMaster-Carr, so I’ll probably end up making my own gantry from some linear actuators I have laying around. But I couldn’t resist giving the files a try.

    Cheers,
    Gavin

    (Yep, I’ve realised that the bed is in upside-down in the photo. Whoops!)

  2. That looks beautiful! This absolutely made my day, thank you!

    It’s really incredible and rewarding, as an open content author, that you can release a project, and literally have folks on the other side of the world putting together something as fantastic as a CT scanner moments later.

    For the particular hardware bits, the design itself is a little flexible on what parts you choose. For the table, any old nut and screw should work, and if you can find one made out of nylon (like the McMaster-Carr part #), then it keeps it nice and light. Hopefully the 4 flange bushings on the base and 8 snap bushings on the carriages are fairly easy to source, and if not we can always resize the holes to make them a more standard size. I think all of the bushings cost $4, and the aluminum rails were $12 total, at the hardware ACE hardware store here. Also, I forgot to mention that the screws for the 4 timing pulleys are 4/40s — two on either side to keep the 6 pieces together, and one (plus a nut) to use as a set screw. They work best if you can screw all the pieces together in a clamp or other jig that can keep them all flat, otherwise they get a little wiggly. It took me a few tries.

    Again, absolutely great work!

  3. Hi,

    I’m thrilled to hear about open source devices entering the medical domain.

    I have some background on image reconstruction in CT systems and would be delighted to work for this project.

    Please let me know if I can help.

    Thanks!

    • Thanks for your note! I think Gav (above) is working on a simple visualization tool to move from the sonograms to image slices in Python for his project, and he might be interested in having a hand? Right now I’m just plugging the data into MATLAB to process, but I also wrote a little demo to show the data as it comes off the machine in Processing for the Tucson mini maker faire last month.

      It sounds like something that would be useful to do would be to make an open dataset with a complete object or two, straight as it comes off the SD card, that folks who want to contribute on the software side can tinker with?

      It seems like there’s a great deal of interest in the OpenCT, so maybe I’ll finish off the Arduino Shield design shortly and bolt on the accelerometer (it just same this week) for measuring the angle of the bore, and do a few complete scans.

    • I think I’ll likely be just an attendee this year, though if they’d like me to present I’m happy to put something together last minute.

      The Mark 5 is going a little slower than I’d hoped — So far I have about two thirds of the sensors working, which is great, and hopefully the other ones will come along shortly. The motherboard is going slow, though — After seemingly working well for a while, I’m having trouble interfacing the FT800 display controller to the LCD. There were apparently some house wiring issues with the place I rent, and when I flicked a switch to turn on a ceiling fan it blew up some of the things on my desk (!) including my bench supply, to which the Mark 5 Arducorder was connected, and then it started behaving funny — so I think I’m going to have to build a fresh one to eliminate explosions from my diagnostics. Many of the components in the Arducorder are also brand new models, so there isn’t currently a good deal of support or reference examples to work from when you encounter a bump in the road.

  4. I assume that you are aware that there are open source libraries and tools for processing CT files in DICOM (Digital Imaging and Communications in Medicine) format. Open source viewers are ClearCanvas (http://www.clearcanvas.ca) for Windows and OsiriX (http:www.osirix-viewer.com) for OS X. http://www.dclunie.com has a great deal of information on imaging.

  5. Hi, we are considering this project for a vision course at our school (polytechnic) and are planning to build a prototype. I was wondering what kind of materials are used. I can’t find a reference to material thickness other than the remark in a post below where 1/8 mdf sheet. Since i am in Europe, the materials sold locally are mostly in mm. If this is the case i may need to do some redesign.

    thanks

    Jan van Hulzen

    • Hi Jan,
      3mm MDF should work just fine — I think the material they sell here as 1/8 (3.2mm) is actually 2.9mm. The mount slots are designed to be a tiny amount oversized to make it relatively easy to put together, where snugging up the captive nuts/bolts are what actually keeps the whole thing nice and rigid.

      Let me know how it goes!

      • We started our build today. It’s quite a puzzle but everything fits nicely. When the build is completed i will post some pictures of our scanner.

        • Very exciting! Please keep me posted!

          About a month ago I put most of the mechanical bits of one together for the demo table at our local hackerspace, Xerocraft. I was surprised that it only took a couple of hours to put the whole thing together — I’d assembled it as I was developing it, so I’d not done one from scratch before. It made me think, “Well, I guess we now live in a time where someone can download a CT scanner from the internet, and put it together in an afternoon…”. 🙂

  6. Nice project!

    We are interested in this project and we would like to pruchase one prototype from yours. Any details about purchase can be provided for us?

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