Abstract: Apparatus for electric tomography comprising a coupling medium for receiving an object to be examined, a plurality of electrodes disposed in the coupling medium and arranged in a three dimensional array; multiplexing apparatus for applying electric voltages at selected first pluralities of electrodes and simultaneously measuring electric currents at corresponding selected second pluralities of electrodes in a desired sequence; and computation apparatus coupled to the multiplexing apparatus for originally estimating the electrical properties at a multiplicity of locations in the object to be examined, these locations being arranged in a three dimensional imaginary grid defined in the object to be examined and subsequently correcting the conductivity estimates at each of the multiplicity of locations on the basis of the measured currents by an iterative process.

Abstract: Apparatus for detecting tumors in living human breast tissue comprising apparatus for determining the dielectric constants of localized regions of living human breast tissue including probe apparatus comprising a multiplicity of probe elements, apparatus for applying an AC signal to the tissue, apparatus for sensing electrical properties at each of the probe elements at a plurality of different times, and signal processing circuitry, coupled to the sensing apparatus for comparing the electrical properties sensed at the plurality of different times for providing an output indication of the dielectric constant of the localized region of breast tissue associated with the probe apparatus.

Abstract: An apparatus for detecting tumors in living human breast tissue includes instrumentalities for determining the dielectric constants of a plurality of localized regions of living human breast tissue. These instrumentalities include a bridge which is provided with a circuit for automatically nulling the bridge while in operation. Instrumentalities are provided for measuring variations in the dielectric constants over a plurality of the regions and for indicating the possible presence of a tumor as result of the measurement. The apparatus may be utilized in carrying out a method of detecting tumors which includes the steps of applying a plurality of probe elements to human breast tissue for sensing characteristics of localized regions thereof, applying an electrical signal to the probe elements for determining dielectric constants of localized regions of the tissue, sensing variations in the dielectric constants and determining the rate-of-change of dielectric constant at each of the localized regions.

Abstract: An instrument for viscoelastic measurement, particularly for breast palpation, uses a plurality of spaced elongated electret strips which are pressed into the body being examined by a pressure member which applies a given periodic or steady stress to the tissue beneath the electret strips. Electronic measuring means then interrogates the output voltage of each of the strips in turn and the output of each strip is displayed to produce a display characteristic which will show the presence of an inclusion in the breast tissue being examined.

Abstract: An instrument for viscoelastic measurement, particularly for breast palpation, uses a sensing transducer head which contains at least two spaced, relatively small area transducers. The transducers can be fixed relative to a glove to be worn by an examiner or can be otherwise supported. The transducers have output leads connected to monitoring circuits which monitor differences in output of the transducers when both are pressed against breast tissue in order to sense thickened areas which may be too small to be sensed by manual palpation. The transducer may be attached to a position monitor so that the transducer head output can be continuously related to the location in space of the transducer head, and the output can be displayed in a suitable display.

Abstract: An apparatus and method for determining a velocity of propagation and the thickness of different substances such as pipe walls utilizes a transducer connected to an A-scan. This material is placed in a holder between the transducer and a reflecting surface, the holder containing a fluid having a known velocity of propagation. The transducer converts high voltage electrical pulses produced by a generator into ultrasonic vibrations and also converts echo signals received from the reflecting surface and the material back into electrical pulses. A display device connected to the transducer displays these pulses and their exact position on the display device is used to determine the velocity of propagation and the thickness of the material.

Abstract: An apparatus for three-dimensional visualization of an object or substance with particular utility for determining the presence of breast cancer contains a dual sensing head having two transducers connected to conventional B-scan equipment. The methodology of this apparatus is based on a new form of ultrasonic imaging that presents perspective views rather than tomograms (cross-sections). These two perspective views are obtained simultaneously by using a pair of cylindrically focused transducers in a scanning unit and are displayed on a monitoring scope in a split screen presentation, which, when viewed as a stereo pair, gives the operator a three-dimensional image of the interior of the scanned object.

Abstract: The present invention relates to an electro-optical imaging device containing as transducer a foil electret, having a transparent conducting backplate.