A radiology technician of the MRI unit. MRI was used for the diagnosis of primary cancer, tumor staging, treatment monitoring, and follow up. Magnetic Resonance Imaging (MRI), or nuclear magnetic resonance (NMRI) is primarily a medical imaging technique most commonly used in radiology to visualize the internal structure and function of the body. MRI provides much greater contrast between the different soft tissues of the body than computerd tomography (CT) does, making it especially useful in neurological (brain), muscoskeletal, cardiovascular and oncological (cancer) imaging. Unlike CT, it uses no ionizing radiation, but uses a powerful magnetic field to align the nuclear magnetization of (usually) hydrogen atoms in water in the body.major components of an MRI scanner are: the main magnet, which polarizes the sample, the shim coils for correcting inhomogeneities in the main magnetic field, the gradient system which is used to localize the MR signal and the RF system, which excites the sample and detects the resulting NMR signal. The whole system is controlled by one or more computers.