What is a computer tomography?
For works in the field of a reconstructive tomography to Alan Cormac and Godfrey Haunsfild the Nobel Prize on physiology and medicine for 1979 was awarded. A. Cormac conducted theoretical researches, and G. Haunsfild in 1972 made the first complex of the x-ray tomograph and computer system of recovery of images. Now computer tomographs are available in any large clinic and hospital. Why they were widely adopted so?
The reconstructive tomography was very powerful tool at statement of the diagnosis. In the x-ray computer tomography (CT) a large number of measurements is made, each of which corresponds to a certain mutual provision of a source and the detector of x-ray radiation. The source and the detector are in the plane of section which image is required to be received. For each combination of the provisions “ a source - the detector “ carry out two measurements: calibration and working. During working measurements of the patient place in the field of reconstruction, and by means of the computer calculate layer-by-layer images of this or that area. Certainly, the step and thickness of such cross cuts can be varied.
It is important to note that the received images have very high degree of permission that allows to differentiate fabrics with the minimum structural distinctions. At the same time images are very similar to cuts, habitual for the clinical physician, which are available in anatomic atlases. Similar other diagnostic testings give nothing. By what else method it is possible to cut virtually the person across and to look that there inside?
At KT the head and a neck, and also chest and belly cavities are most often investigated. The KT greatest value has in traumatology when it is necessary to define existence of these or those damages, in neurosurgery and at research of vessels. In oncology of KT it is used for definition of degree of prevalence of tumoral process and when planning radiation therapy.
It is also worth noting that radiation levels at KT are in most cases lower, than at research on the ordinary X-ray diagnostic device. And the image in the cross plane, inaccessible at standard radiodiagnosis, often is extremely necessary for statement of the exact diagnosis.
Research happens as follows: the patient lies on a table which slowly moves in the rotating ring. On a ring on the one hand there is a x-ray tube, and with another - a matrix of detectors of ionizing radiation. After a whole revolution of a x-ray radiator and detectors around a table on the screen of the computer the cut of the studied body appears. Information on body gathers a cut behind a cut. As a rule, research lasts no more than one hour, and for some areas, for example for the head, takes only several minutes.
It is necessary to mention also other type of a computer tomography - about diagnostic testings with use of effect of a magnetic resonance (MR - a tomography). Clinical experience testifies to high resolution and high picture contrast of fabrics at MR - a tomography. Besides, in computer tomographs on the basis of effect of a nuclear magnetic resonance there are no sources of ionizing radiation and therefore diagnostic testings on MR - tomographs are almost completely safe for patients.