"Just lay down on that table, and hold still while we orient the polarization of all the water in your head. It'll be just fine." CTs (http://en.wikipedia.org/

"Just lay down on that table, and hold still while we orient the polarization of all the water in your head. It'll be just fine." CTs (http://en.wikipedia.org/wiki/X-ray_computed_tomography http://en.wikipedia.org/wiki/X-ray_computed_tomography) and PETs (http://en.wikipedia.org/wiki/Positron_Emission_Tomography http://en.wikipedia.org/wiki/Positron_Emission_Tomography) are pretty cool as well. CTs use essentially an X-ray beam that travels in a helical path around your body, and then use math to construct a 3D image, PET is the one where you drink an isotope, and they "catch" the positrons emitted from the radioactive material in your body.