[Ben Krasnow] Builds A CT Scanner


After building a homebrew x-ray backscatter imager, [Ben Krasnow] realized he had nearly all the components to build his own CT scanner, able to make a 3D model of the inside of a frozen chicken.

Basically, a CT scanner takes dozens of x-rays of an object and reassembles them with the help of fancy algorithms to allow doctors to peer inside a human body. The CT scanners you’ll find at your local hospital are monstrous devices, rotating an x-ray tube and sensor around a patient with the help of some very heavy duty electromechanical engineering. [Ben] wanted to keep his build rather small, so instead of rotating the x-ray tube and screen around an object, he simply made a stepper motor-driven lazy suzan to rotate his frozen bird.

[Ben] set a digital camera off to the side of his build and captured 45 images of a rotating chicken. After correcting for the perspective distortion, the images were thrown into 3D Slicer to create a true 3D representation of a x-rayed chicken.


44 thoughts on “[Ben Krasnow] Builds A CT Scanner

    1. No, he’s clearly not being safe.

      Do you see any shielding?
      Do you notice all the objects that are reflective to Xrays? Nearly everything generates backscatter, too.
      Do you see any xray radiation measurement devices, so he knows what his exposure is?
      Do you see him talk at all about protective equipment, or post warnings in the youtube video descriptions?

      He’s doing 45 minutes of xray exposure total here, which is WAY more than a typical exposure; I’ve had a CT scan done of my wrist. It took a minute or less, it was just of my hand, and the rest of me was shielded with screens and blankets. The tech stood in a room shielded with lead. Anything or anyone downstream of the tube’s window is getting exposed to a significant amount of radiation, and xray radiation is NOT something you mess around with!


      People: stop screwing around with Xrays!

      1. Settle down. People should take more risks and advance our understanding of the world rather than be so overly-concerned with safety all the time. The man knows how to make a CT scanner, I think he merits being left to his own safety guidelines.

        Your counterexample is poorly thought out. 1) You assume that the amount of safety precautions are actually what is merited by that one exposure and not the result of hyperventilating safetyniks. 2) The tech has to do scores or hundreds of scans a day for years. The precautions are likely calibrated to that level of long-term exposure.

        Some of the knowledge we have gained can and is being used to make the experimenters safer, and that’s fine and dandy. But let’s not lose sight of the goal here.

        Progress First! Safety third.

      2. Holy Hall Monitor!

        You were that pain in the butt kid that always tattled when he found out someone was doing something possibly dangerous and or fun. I’ve always wondered; was your tattle tale behavior motivated by concern, fear, envy or some combination thereof?

        Obviously the video is a tl;dr issue for you, so let me point you to the part you would be comforted by: http://youtu.be/hF3V-GHiJ78?t=4m5s


  1. Whaaaat?

    Seriously. Impressed.

    I don’t even want to watch the video. It will only make me feel more depressed at how far behind I am. I’ll just stare at the spinning chicken in awe.

  2. Is anyone else thinking “hmmm – frozen chicken, I wonder what he did after he was finished with this very cool experiment. After 45 minutes it was partially thawed out so it was either bin or oven”
    Which would you do ?

  3. Any chance of him getting a 3d printer and scanning a chicken McNugget? If so I think he could put McDonalds out of business because the 3d Printed McNugget would probably be less chewy and taste better.

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