ACTIVE SHIELDED HIGH-ORDER GRADIENT COIL FOR THE HEAD

摘要

PURPOSE: A shielded high-order gradient magnetic coil for photographing a head is provided to reduce the number of RF pulses for selecting a three dimensional space to decrease the artifact generated during the space selection and increase an SNR(Signal Noise Ratio), and to offset the intensity of a high-order gradient magnetic field generated from a primary layer coil to damp the amount of an eddy current for compensating the eddy current generated by the change of the magnetic field. CONSTITUTION: A primary layer coil(a) generates a high-order gradient magnetic field. A shield layer coil(b) removes an eddy current generated by the primary layer coil(a). An RF coil(c) receives an NMR signal. The primary layer coil(a) is positioned in between the shield layer coil(b) and the RF coil(c), and the lengths of respective coils(a,b,c) are different from each other to form an asymmetrical structure.