The essay "Magnetic Resonance Imaging Technique" talks about an advanced imaging technique used in the field of medicine under radiology particularly how it works.
All bodies expose themselves to water molecules. The water molecule has two protons and hydrogen nuclei. When one is using a powerful magnetic field of a scanner, the overall magnetic moment of different protons aligns themselves in the direction of the field. Turning on of the radio frequency transmitter follows, thus, producing different electromagnetic fields. The electromagnetic field has the appropriate frequency termed as resonance frequency; the protons in the magnetic field absorb and flip the spin. After a while, when the electromagnetic field is in off status, the protons’ spins get to thermal dynamic equilibrium. The bulk magnetizations get aligned by the static field. As a result, this relaxation, radio frequency signals arise; these can be measured using receiver coils.
Additional magnetic fields can facilitate learning about the information regarding the origin of the 3D space during the scan. Fields generated by passing electrical current via gradient coils results to varying magnetic fields in reference to the position of the magnet. This also alters the frequency of the signal, as it depends on the origin of the signal. Mathematically, the distribution of the signal can also be recovered from the body; however, this uses the inverse frontier transformation. After the relaxation rates, protons in various tissues return to the equilibrium.