Patent ID: 7343192

Claim:
A method for analyzing composition of a body portion, comprising: inducing a substantially homogeneous static magnetic field and a substantially uniform gradient magnetic field in an entire body, a gradient of the gradient magnetic field being along a predetermined axis of the body; inducing a substantially homogeneous radio frequency magnetic field in the entire body while inducing the combined static and gradient magnetic fields, the radio frequency magnetic field having a frequency and a bandwidth selected to excite nuclear magnetic resonance phenomena in a segment of the body along the axis; determining at least an amplitude of a nuclear magnetic resonance signal; adjusting at least an amplitude of the static magnetic field and repeating the inducing the radio frequency magnetic field and determining at least the amplitude of a nuclear magnetic resonance signal from another segment of the body along the axis; determining a portion of the body for analysis from the at least the amplitudes of the nuclear magnetic resonance signals; selecting at least an amplitude of the static magnetic field and a gradient of the gradient magnetic field to excite nuclear magnetic resonance phenomena in the determined portion of the body, the gradient selected such that the determined portion has a selected size along the axis; inducing a radio frequency magnetic field in the entire body; detecting nuclear magnetic resonance signals from the determined body portion; determining a mass of at least one constituent in the determined body portion from the detected nuclear magnetic resonance signals therefrom; and at least one of displaying and storing the determined mass.