The medical scanners use very large magnets because the field has to be uniform. If you can live with lower resolution then you can use a weaker field. The medical scanners use high strength fields so that they can use higher frequency RF photons, which have correspondingly shorter wavelengths which gives them more resolution. The preceeding will be true for any strength magnetic field. This absorbs energy from the RF pulse (which can be measured), and at some future time the nuclei will flip back and emit an RF photon (which can also be measured). While spinning, if you pulse an RF signal at the frequency of rotation, you can get the nuclei to flip end-for-end. It spins around this field with a speed of rotation which is a function of the strength of the field. The nuclei can’t line up perfectly with the magnetic field because that would violate the uncertainty principle, so it has to point at some angle from the external field. The magnetic field causes certain atomic nuclei to spin and precess like a top wobbling. Posted in chemistry hacks, Medical Hacks Tagged ct scanner, radioactive, Tomography Post navigation still has some work to do on his desktop CT scanner, but once the stepper motor and sensor board are complete, he should be well on his way towards scanning carrots, apples, and just about everything else around his house. This doesn’t bother, as ‘free’ time on a CT scanner allows for some very interesting, not seen before visualizations, such as a plant growing from a seed, spreading its roots, and breaking the surface as a seedling. The machine operates just above normal background radiation, so while being extremely safe for a desktop CT scanner, it is, however, very slow. As for the source, is going for very low intensity sources, most likely Barium or Cadmium that will take many minutes to capture a single slice. Not only does this allow for an easy interface with a microcontroller, it’s also much smaller than big, heavy photomultiplier tubes found in old CT scanners. This, combined with the rotation of the disk and moving the bed back and forth allow the imager to position itself anywhere along an object.įor the radioactive detector, is using a CCD marketed as a high-energy particle detector by Radiation Watch. The mechanics of the build are a Stargate-like torus with stepper motor moving back and forth inside the disk.
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These slices can then be recompiled into a 3D visualization of the inside of any object. Instead, is building a CT scanner, a device that takes multiple x-ray ‘slices’ around an axis of rotation. A good thing, that, as superconducting magnets chilled with liquid helium is a little excessive for a desktop unit. This isn’t an MRI machine that so fondly remembered from grad school.
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A few weeks later, the beginnings of an open source CT scanner began to take shape.
#Low cost low exposure x ray free
A few years into his doctorate, found himself in a very opportune situation – his local hackerspace just acquired a shiny new laser cutter, he had some free time on his hands, and the dream of creating a medical imaging device was still in the back of his mind. For, the most interesting course in grad school was Advanced Brain Imaging each class was a lecture followed by a trip to the imaging lab where grad students would take turns being holed up in a MRI machine.
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