Az MRI története, dinamikus szájüregi és maxillofaciális alkalmazása

Abstract

The incredible evolution of medicine in the 20th century was made possible by the appearance and rapid innovation of diagnostic procedures. The discovery of the medical application of X-rays gave the opportunity to image the human body without disrupting tissue structure. The use of X-rays spread around the world at an incredible speed and almost all medical fields, including dentistry, began to use them. In the second half of the 20th century, exponential improvement of computing technology replace the summation scans with a new three-dimensional technique, Computer Tomography. Cone Bean CT scanners (CBCT), which use a non-traditional cone-shaped beam as a radiation source, have made three-dimensional imaging widely available in dentistry. However, the harmful side effects of X-rays soon came to the attention of the public, and further research led to the development of a previously unknown technique, magnetic resonance imaging (MRI). This device was the result of the collaborative work of many scientists, mainly physicists. From the experiment by Isiodor I. Rabi, who proved that the atomic spin of nuclei can be changed in a magnetic field, to the scientists involved in the development of nuclear magnetic resonance spectroscopy, to the experiment of Paul C. Lautenburg, who was the first to create an image using this method. Raymond Damadien demonstrated that the NMR signal of tumour tissue differs from that of healthy tissue, thus providing the basis for the medical application of the method. Sir Peter Mansfield's new method greatly reduced the scanning time, allowing fast-moving organs such as the heart to be imaged. The measurement of contrast medium, and soon afterwards of blood oxygenation, made it possible to perform functional MRI examinations. The use of positron emission tomography combined with three-dimensional imaging techniques gives accurate diagnostic results, can be preferable in certain clinical situations and provides similar results at lower radiation levels. In terms of maxillofacial applications, CT and MRI scans are mainly used in cases of oral cavity tumour abnormalities. In dentistry, the imaging technique used in everyday practice is the CBCT, a non-traditional cone beam technique, which allows better quality images to be obtained in a shorter exposure time and using a lower dose of radiation.