3 ms·

are these the guys that did the scan of a pumpkin. is that what they made the powerful scanner for

• jlokier 5y ago
  No, that was a CT scan. Different operating principle. CT scan uses X-rays beams from many angles, like taking X-ray photographs from different angles, and the images are combined mathematically into a 3D image. X-rays are a lot like regular visible light, they travel in straight beams and form clear images when focused, except unlike visible light, many substances are more transparent to X-rays. MRI uses radio signals in the microwave or below frequency range combined with a high strength magnet with a shaped magnetic field to make a field strength gradient. The radio waves resonate with some atomic nuclei at a frequency which depends on the magnetic field strength, so the combination of magnetic field gradient and radio frequency creates a thin layer in space where resonance occurs, affecting the radio waves in that layer while they pass through the rest of space much less affected. The layer is moved around, radio receivers pick up the affected signal, and the 3D image is reconstructed from that signal.
• kergonath 5y ago
  The pumpkin here is just a test. They are still tuning it and at some point want to look at brains with a 100 μm resolution. They just cannot put living people in it before it’s been tested and certified.
• mattkrause 5y ago
  Fruit and vegetables are pretty popular test objects: they sit nice and still, they have interesting structures (i.e., look cool), and they avoid ethics/safety issues involved in scanning humans or animals. "Phantoms", test devices with specific and well-known properties, are used for more careful testing but produce works pretty well for a quick sanity check.