| 摘要 |
PURPOSE:To improve the precision of frequency resolution, the ability of position resolution and to obtain a three-dimensional nuclear spin density distribution, by repeating continuously two times or more the step impressing a gradient magnetic field whose intensity is varied in accordance with the position of one axis direction in a surface of the slice part while changing said part. CONSTITUTION:A material body to be measured is laid under a uniform magnetic field H, the gradient magnetic field GZ(Z1) and a high-frequency excitation signal RF(R1) are impressed simultaneously in a term 1, and a spin is excited selectively at the slice part (Q1). The gradient magnetic field GY(Y1) in which the magnitude of the magnetic field is varied in the axis direction perpendicular to a Z axis, e.g. the position for Y axis direction is impressed in a term 2 for prescribed time T1. A gradient magnetic field GZ(Z3) and a high-frequency excitation signal RF(R2) are impressed in a term 3 as in the term 1, and a spin is excited selectively at the slice part (Q2). The gradient magnetic field GZ(Z3) and the signal RF(R2) are impressed in terms 5 and 6 to excite the slice part (Q3), then the step for impressing the gradient magnetic field GY(Y3) is performed. |
