text: <unk>  <unk> , formerly referred to as<unk>  resonance tomography (MRT) and, in scientific circles and as originally marketed by companies such as General Electric, nuclear<unk>  (NMRI) or NMR zeugmatography<unk> , is a non-invasive method using nuclear<unk>  resonance to render images of the inside of an object. It is primarily used in medical<unk>  to demonstrate pathological or other physiological alterations of living tissues.<unk>  also has uses outside of the medical field, such as detecting rock permeability to hydrocarbons and as a non-destructive testing method to characterize the quality of products such as produce and timber.<unk>  should not be confused with the NMR spectroscopy technique used in chemistry, although both are based on the same principles of nuclear<unk>  resonance. In fact<unk>  is a series of NMR experiments applied to the signal from nuclei (typified by the hydrogen nuclei in water) used to acquire spatial information in place of chemical information about molecules. The same equipment, provided suitable probes and<unk>  gradients are available, can be used for both<unk>  and spectroscopy.
  The scanners used in medicine have a typical<unk>  field strength of 0.2 to 3 Teslas. Construction costs approximately US$ 1 million per Tesla and maintenance an additional several hundred thousand dollars per year.<unk>  units can operate up to 21.1 Teslas (in the case of a 900 MHz unit; see the magnetogyric ratio and Larmor frequency).
option_0: Magnetic resonance imaging
option_1: MRI sequences
option_2: Magnetic resonance angiography
option_3: Functional magnetic resonance imaging
option_4: Pain MRI
option_5: Ultrasound
option_6: Pain x ray
option_7: Earth's field NMR