Doctors and scientists are able to view the three dimensional format on a computer screen. .
MRI stands for magnetic resonance imaging. This scan uses magnetic fields, radio waves and computer enhancement to provide much better images of brain structure and function than CT scans. Once called nuclear magnetic resonance imaging, the "nuclear" was dropped off because of fears that people would think there was something radioactive involved, which there is not. MRI is a way of getting pictures of various parts of the body without the use of X rays, unlike regular X ray pictures and CT scans. An MRI scanner consists of a large and very strong magnet in which the patient lies. A radio wave antenna is used to send signals to the body and then receive signals back. These "radio wave signals" are actually a varying or changing magnetic field that is much weaker than the steady, strong magnetic field of the main magnet. These returning signals are converted into pictures by a computer attached to the scanner. Pictures of almost any part of your body can be obtained at almost any particular angle.
PET stands for positron emission tomography, and it is much more complicated than the CT scan. A PET scans is a medical imaging technique that provides images of biochemical function over time. This enables researchers to map which areas of the brain become active to specific stimuli. PET machines bombard the subject with doses of positrons: the anti-matter equivalents of the electrons. As the positrons enter the body, they encounter electrons that are escaping from radioactive elements that have been injected into the bloodstream. When the positrons and the electrons collide, they give off energy that is recorded by a computer. The result of this scan is a detailed 3-D picture of the brain.
The SPECT, which is the short form for Single Photon Emission Computed Tomography, is a device that resembles the PET.
