NMR in medicine

Nuclear magnetic resonance (NMR) offers a powerful new probe of the body's internal anatomy and function. The technique utilizes a combination of static and radio frequency (RF) magnetic fields to excite a weak resonant magnetic field emission from various selected naturally abundant nuclei in the body such as hydrogen (¹H), phosphorus (³¹P) and carbon (¹³C). The emissions can be spatially encoded by application of magnetic field gradients, to enable the generation of high resolution anatomical images which reflect the nuclear density distribution, and/or spatial variations in the molecular level and chemical environments of the nuclei as measured by the NMR relaxation times and chemical shifts. ¹H NMR relaxation time images are proving useful for the detection of a wide spectrum of disorders, whilst spatially localized ³¹P and ¹³C NMR chemical shift spectra measure directly the metabolic status of living tissue. A qualitative explanation of NMR, NMR imaging, relaxation times, and chemical shifts is presented, and the historical development, future of the technology, and its range of applications explored.