advances in nuclear medicine. Although X-ray machines have been the chief.
mechanical tools for internal observations of the human body since Wilhelm.
Roentgen discovered X-rays in 1901, the development of computers made it.
possible for better and more accurate techniques to be applied to scan the.
human body. These methods employ various scanners like the CAT, PET, MRI.
and SPECT.
The CAT is an acronym for Computerized Axial Tomography. This method.
of scanning generally involves X-rays and enables scientists to view the.
inside of the head in a three dimensional format on a computer screen. PET.
stands for Positron Emission Tomography and it is much more complicated.
than the CAT scan. 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 which are escaping from.
radioactive elements which have been injected into the bloodstream. When.
the positrons and the electrons collide, they give off energy which is.
recorded by a computer. The result is a far more detailed 3-D picture of.
the brain than the one obtained from the CAT machine. To obtain an even.
better image, physicians use the MRI, which stands for Magnetic Resonance.
Spectroscopy. With these three processes combined, every structure of the.
body can be easily observed. The CAT and the MRI are c ently being used to.
detect early signs of Multiple Sclerosis in patients who show MS symptoms.
The SPECT equipment is a brand new addition to the family of body.
scanners. It is still in experimental mode at several United States.
hospitals, but it has received much positive criticism. The SPECT, which.
is the short form for Single Photon Emission Computed Tomography, is a.
device which resembles the PET. However, it uses radiation which is less.
harmful and the tracers which are injected into the patient are non-.
radioactive isotopes of Lithium, Carbon and Phosphorus.
