NSCI 201 Lecture Notes - Hurlburt Field, Rela, Visual Cortex
19 Apr 2012
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Document Summary
Dpding on composition of the, obect the image produced will be different: not hard tissue: x-rays pass through, detect many events, hard tissue: x-rays don"t pass through. Use radioactive tag on the sugar, put in bloodstream: sugar is radioactive thus emits radioactive particles. Common isotope uses flu-18, which emits radioactive particles (positrons) which hit nearby electron, causing. 2 gamma rays to shoot out at 180 degrees from each other: circle of crystal detectors uoresce when hit by gamma rays. Rays emitted in proportional to amt of sugar taken up (and thus the activity of brain: computer looks for 2 detectors 90 degrees apart that have ashes occur simultaneously; computer draws a line btwn the two. Signal is called net magnetization and its value dpds on ratio of protons in energy parallel state to high energy anti parallel state (b) apply energy from a right angle to the protons to change their orientation.
