Resonex, Inc.

Cardiac Mariners, Inc.

Brian P Wilfley

Edward Gerald Solomon

David M Parish

Robert J Perlmutter

Craig H Barratt

John Moberly

Rick Motamedi

Robert J Perflmutter

A method for scanning an x-ray target in a reverse geometry x-ray imaging system with a charged particle beam is disclosed. An aspect of the invention is directed to scanning patterns for moving an electron beam across the target assembly to generate x-rays, in which a charged particle beam is moved across a plurality of sets of positions on a target assembly, wherein particular positions or sets of positions on the target assembly are rescanned a plurality of times during a single frame. The length of time between a first and a last illumination of the object during the frame is sufficiently small to prevent image blurring during image reconstruction.

X-ray scanning method and apparatus

External field compensation is provided for MRI apparatus which is in a magnetically noisy environment such as that caused by nearby subway trains. By means of a magnetometer type sensor, the external field fluctuation is sensed and after being adjusted for the filtering effect of the magnet structure of the MRI device itself, the master oscillator of the MRI device is adjusted to compensate for the external field fluctuation. Alternatively the current of the magnet coil is adjusted.

MRI apparatus with external magnetic field compensation

In an MRI method for optimizing flip angles for unequal delay times, a mathematical relationship is derived where RF flip angles can be determined to provide output signals which are constrained to be equal in amplitude and maximized in a sequence of MRI imaging.

Method of optimizing flip angles in MRI for unequal delay times

In an improved NMR imaging method, where three-nominally orthogonal gradient fields are generated, the quantization error of the phase encode gradient is reduced without the necessity of a digital to analog converter of higher bit capacity. This is accomplished in one embodiment by providing a second smaller gradient waveform which is relatively narrow compared to the primary gradient waveform, the ratio of the waveforms being proportional to the improved resolution. The second waveform can occur either before or after the 180.degree. excitation pulse used to produce a spin-echo signal. In another embodiment pulse width modulation is used to vary the area of the phase encode waveform in discrete increments.

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Los Altos, CA, United States of America

Brian P Wilfley