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bar magnet and most MRI (magnetic resonance imaging) has been generated using hydrogen-1 resonance. By the mid 1980s, MRI of hydrogen-1 nuclei was being used to locate tumors, strokes, multiple sclerosis, scars and other lesions. The clinical usefulness of MRI is that no X-radiation is delivered to the body. This means that MRI can be used safely in infants, children and pregnant women. MRI will probably replace CAT and other forms of X-ray imaging in diagnostic radiology. C. PETT
New computer imaging techniques have made possible a sophisticated version of radioisotope scanning called PETT, or positron emission transaxial tomography. An injected radioactive isotope moving through the body emits positrons which collide with electrons in body cells resulting in mutual annihilation and release of gamma rays. A computer turns the information into a coloured map of the body's metabolism. The PETT scan could eventually become a routine part of psychiatric diagnosis of more than one kind of mental illnesses.' D. Evoked Potential Testing
Measuring the electrical activity of the brain is another way of finding disorders and exploring brain function. Minute changes (evoked potential) in electrical voltage, are the brain's response to sensory: stimuli and the computer can identify the specific brain-waves created by the stimulus. Evoked-potential testing is ideal for detecting vision and hearing defects in newborn infants and can prevent life-long impairment. It can also be used to determine the cause of a child's poor scholastic performance, to assess brain damage, to diagnose brain tumors and multiple sclerosis.
E. Neurosurgery / microsurgery
Important progress in the treatment of brain disorders has also been achieved through drug research and advances in neuro-surgical
1. A PETT scanner machine costs several million dollars and requires thirty people to produce one diagnostic scan.
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