| 摘要 |
A magnet system for generating a high-frequency field in an image-generating apparatus of the type which utilizes nuclear magnetic resonance technology, such as zeugmatography. The magnet system contains a pair of magnet coils which are arranged on an imaginary cylindrical surface and which generate a substantially homogeneous high-frequency field which is oriented radially with respect to an axis of the imaginary cylinder. A relatively large signal-to-noise ratio is achieved by utilizing frequencies of, for example, 20 MHz. The magnet system is further provided with at least a second pair of magnet coils which is arranged on at least one imaginary cylindrical surface, and rotated in the circumferential direction. The second pair of magnet coils receives a high-frequency current which is shifted in phase by a predetermined phase angle with respect to the current flowing through the first coil pair; the currents having substantially equal amplitudes. In this manner, a circularly polarized high-frequency field is produced.
|
