Abstract: A tissue testing chamber having a hollow, electrically insulative housing separable into two parts or halves, each half including a plate-like working electrode and spaced therefrom an annular measuring electrode, with electrical leads provided to each of the electrodes for interconnection with external control and measuring equipment. Each housing half or test chamber half has a cavity communicating with both the working and measuring electrodes and an open end. The housing halves clamp the test specimen between them. A quantity of Ringer's solution is added to each housing cavity and the four electrodes are then connected in a four electrode impedance bridge with selectively variable impedances (e.g., capacitance) which on bridge balance provides capacitance of specimen.

Abstract: Two probes for tissue impedance measurement each have first and second conductive rings unitarily arranged with an insulative member separating the rings. The conductive rings are coaxially arranged and have individual lead wires connected thereto which extend from one end of the probe for connection to external processing and measuring equipment. One probe is of a size enabling insertion within a blood vessel while the other is for location in an epithelial cavity. In use an alternating test signal is applied to the electrodes of each probe and measurements are taken between the two sets of measuring electrodes determining the impedance of the cavity wall tissue lying between the two probes without passing current through the tissue.

Abstract: Two probes for tissue impedance measurement each have first and second conductive rings unitarily arranged with an insulative member separating the rings. The conductive rings are coaxially arranged and have individual lead wires connected thereto which extend from one end of the probe for connection to external processing and measuring equipment. One probe is of a size enabling insertion within a blood vessel while the other is for location in an epithelial cavity. In use an alternating test signal is applied to the electrodes of each probe and measurements are taken between the two sets of measuring electrodes determining the impedance of the cavity wall tissue lying between the two probes without passing current through the tissue.

Abstract: The non-invasive testing of soft body tissue is accomplished with the use of a beam of ultrasonic energy which may be focused at varying depths in a patient. The energy content of the ultrasound beam is varied as a function of depth of focus to thereby employ the minimum energy required for proper resolution at the chosen examination depth. Signals commensurate with echoes received by a transducer having an array of coaxial annular electrodes thereon are combined in a manner which results in a good signal-to-noise ratio and minimum attenuation thereby improving the quality of the information derived from the examination procedure.

Abstract: A beam of ultrasonic energy is scanned through the use of a steerable mirror positioned in a liquid path traversed by the beam between a transmit-receive crystal and the target. The mirror is comprised of a material selected to have an angle of excitation of surface waves at the liquid-mirror interface which lies outside the range of angles of transmission and reception incidence at which the beam impinges on the mirror.

Abstract: Side lobe suppression is optimized in an ultrasonic generator by actively driving the transducer crystal with a signal which varies in magnitude. In a preferred embodiment a phased array of annular electrodes on a transducer crystal are individually driven with voltages having a predetermined wave form. The drive voltages are produced by generating a periodic signal and thereafter modulating this signal to provide an envelope which has the desired wave form.

Abstract: Non-destructive testing with ultrasonic energy is performed by scanning a focused ultrasound beam until a region of interest is detected and rescanning this region with the beam focused at a plurality of depths. Apparatus for ultrasonic body scanning for medical purposes may include an actively driven transducer crystal which may be dynamically focused. A beam of energy produced by the transducer will be coupled to the patient by a liquid path and a movable mirror may be interposed along the liquid path to cause scanning of the beam.