X-Message-Number: 3659 From: (Brian Wowk) Newsgroups: sci.cryonics Subject: Re: Medical scanners Date: 9 Jan 1995 21:00:13 GMT Message-ID: <3es84t$> References: <> Joe has explained MRI (NMR) well, so I'll tackle the remaining two. SPECT- Single Photon Emission Computed Tomography SPECT, also known as Nuclear Medicine or Gamma Camera radiography, builds a three dimensional image of organs by detecting gamma rays emitted by injected radioisotopes. Images are typically noisy and of low spatial resolution. PET (Positron Emission Tomography) is a two-photon version of SPECT that achieves better image quality by simultaneously detecting two gamma rays emitted in opposite directions by positron annihilation and then triagulating to determine the source position. SQUID (superconducting quantum interference device) is the technological innovation that makes Magnetoencephalography (MEG) possible. MEG detects the extremely subtle changes in magnetism created by neuronal acitivity and allows the acquisition of crude brain activation maps. --- Brian Wowk Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3659