Get To Know the Science Behind Nuclear Magnetic Resonance Imaging
Medical imaging is considered to be one of the most important tools for diagnosis and treatment. The advent of computers has affected different industries including health sector. Important diagnostic techniques such as Computer Assisted Tomography with X-rays and Magnetic Resonance Imaging with atomic nuclei are two such examples where computers are used for medical analysis.
Nuclear magnetic resonance imaging is done to detect the presence of protons by subjecting them to a large magnetic field to partially polarize the nuclear spins. These nuclear spins are excited with properly tuned radio frequency (RF) radiation, and then weak radio frequency radiation is detected from them as they "relax" from this magnetic interaction. The frequency of this proton "signal" is relative to the magnetic field to which they are subjected during this relaxation process.
During nuclear magnetic resonance imaging, an image of a cross-section of tissue can be obtained by producing a well-calibrated magnetic field gradient across the tissue so that a definite value of magnetic field can be associated with a given location in the tissue. This way you can gather information to map the tissue in terms of the protons present there. Since the proton density varies with the type of tissue, a definite amount of contrast is achieved to capture image of the internal organs and other tissue variations in the subject tissue.
To obtain a three-dimensional image by nuclear magnetic resonance imaging technique, it is essential to add a small field gradient to the large uniform magnetic field, whose direction can be altered by varying the currents through a set of carefully controlled coils.