Gray scale echography with simultaneous a mode presentation a new apparatus for high resolution ultrasonograms
A diagnostic ultrasonic system has been developed for simultaneous display of quantitative A mode and gray scale B mode presentations. An independent calibrator and preset amplification levels allow the apparatus to be calibrated for precise, repeatable examinations. A wide range of echo amplitude information is available to the clinician by the use of selective logarithmic signal compression. Distance measurements in the eye and the orbit are made to 0.1 mm precision and are displayed numerically on the control panel. The newer signal processing techniques provide high‐resolution imaging of ophthalmic structures over a wide system bandwidth. Sensitivity has been improved to image structures heretofore not observable with ultrasonic instruments. This technique is the basis for recently initiated clinical studies.
Application of integrated electronics to ultrasonic medical instruments
During the past decade, ultrasonic medical diagnostic instruments have advanced significantly as a result of the resourceful application of electronic-system and acoustic-transducer designs to the problem of noninvasive information acquisition from clinical patients. These advancements are reviewed, with emphasis on the electronic technology by which they were achieved. Current instruments that enable imaging through real-time scanning and gray-scale display are described. It is predicted that future ultrasonic diagnostic instruments will be based on increasingly sophisticated integrated electronic technology that should greatly enhance the imaging performance of these systems; it should also provide the foundation for ultrasonic imaging instruments that will extend the state of the art in quantitative analysis and diagnosis through doppler processing. This growing technology most likely will include 1) high-current DMOS multiplexer transmit/ receive switches, 2) precision preamplifier array circuits, 3) advanced beamsteer/focus delay lines, 4) multielement integrated transducer arrays, and 5) Doppler-processing integrated circuits.
Imaging the in-plane magnetization in a Co microstructure by Fourier transform holography.
We report on experiments using Fourier transform holography to image the in-plane magnetization of a magnetic microstructure. Magnetic sensitivity is achieved via the x-ray magnetic circular dichroism effect by recording holograms in transmission at off-normal incidence. The reference beam is defined by a narrow hole milled at an inclined angle into the opaque mask. We present magnetic domain images of an in-plane magnetized cobalt element with a size of 2 μm × 2 μm× 20 nm. The domain pattern shows a multi-vortex state that deviates from the simple Landau ground state.