Method and apparatus for examination by nuclear magnetic resonance

摘要

An examination method and apparatus utilizes a nuclear magnetic resonance technique in which the body of a subject to be examined is placed in a uniform static magnetic field and subjected to an electromagnetic wave having a frequency which induces nuclear magnetic resonance, a magnetic field is also applied to the subject body to specify an area of the body from which nuclear magnetic resonance (NMR) signals are radiated, and such nuclear magnetic resonance signals from the specified body area are received. A first 90 DEG pulse as the electromagnetic wave is applied to the body to excite the same, and then a 180 DEG pulse is applied to the body to produce an echo signal. A second 90 DEG pulse is to the body when the echo signal is maximum to thereby allow a magnetization to return to a state of thermal equilibrium. The foregoing sequence of the steps is repeated at prescribed intervals.