The brain always has fascinated the physicians and the general public. The dreaming, the speech, the hearing, the memory, the equilibrium, etc., but over all, the interpretation and processing of information, are some of the amassing functions of the brain. Even the most sophisticate actual computer do not equal these functions. The physicians investigate the functions of the brain using techniques from high energy physics. The results would affect the computater science, informatics, telecomunications, and other science branches. Maybe, after that investigations the scientist will be more fascinated by the functions of the brain.
The idea in these investigations is very simple. The activity of the different areas of the brain and the blood flux are very close related. The higher the activity, the bigger the blood irrigation of the area. Dead areas, or inactive ones, are poorly irrigated. To monitor the blood irrigation of some areas of the brain is to monitor its activity. The physicians register the cerebral activity using radioactive probes.
The physicians use the xenon 133, it is a radioactive xenon isotope. They used it as a probe. They inject it diluted in sterile physiological serum to the patient in the arteries that irrigate the brain. The radioactivity probe, transported by the blood, indicates the blood flux. The physicians detect the gamma rays, originated from the disintegration of the xenon 133, through arrays of scintillator detectors located outside the body. Each one of the detectors explores and monitors a square centimeter of the cerebral area. The physicians process the information from the detectors using a computer. They project the image on a chromatic TV monitor. The different regions in the cerebral cortex and their respective activities are visualized in different colors, indicating the intensity of the blood irrigation. The detected radiation comes from cerebral cortex, for that originated from the more deep regions is attenuated. Therefore the technique of xenon gives a clear image of the cerebral cortex and of its activity.
But the cerebral cortex is only one part of the brain. The physicians use complementary techniques to explore the whole brain, specially the internal regions. The computarized tomography, the nuclear magnetic resonance, the tomography by positron emission, the pulsed fluoroscopy, etc. All those techniques complement the studies.