| 摘要 |
<p>A magnetic resonance system is provided which employs a shielded, electromagnetically asymmetric and low-stress magnet to produce a superior sized imaging region close to the patient side. The magnet has a double layered configuration. In the primary layer, the magnet includes at least two strongest coils at two ends of the magnet (end coils), which carry current in the same direction. The magnet may include at least one coil close to the end coils which carries current in a direction opposite to that of the end coils. The magnet employs a plurality of smaller sized coils (4-7, relative to the large end-coils) in the central region of the primary layer, and these coils are located asymmetrically relative to the imaging region centre. The magnet is shielded by a plurality (1-5) of shielding coils, which carry current in a direction opposite to that of the end-coils at primary layer. Compared with conventional short-bore magnets, the magnet of the invention offers an accessible imaging region with significantly enlarged imaging region, and it can be used in, for example, body-part or whole-body imaging.</p> |
