Nuclear magnetic resonance imaging and its safety implications: follow-up of 181 patients

Nuclear Magnetic Resonance (NMR) is a new method for imaging the human body. Its images are displayed in a manner similar to X-ray CT but there the similarity ends. Whilst X-ray CT uses X rays to produce an image of the different coefficients of absorption through a section of the body, NMR depends on the responses of hydrogen protons to a radio-frequency and does not require ionising radiation. The phenomenon of NMR has been known since 1946 (Bloch, 1946; Purcell et al, 1946) and is widely used as an analytical tool in physics and chemistry. In 1971 the concept of using the NMR technique for detecting malignant tissue was introduced (Damadian, 1971) and by 1973 NMR images of phantoms had been made (Lauterbur, 1973).