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. The system is also much faster which permits quicker diagnoses.