Abstract: An MRI breast coil is provided with a large transverse access portal and a stereotactic frame for guiding a biopsy needle. The portal is covered by thin sheath of plastic to retain the breast but still allow insertion of the needle to any location. The frame aligns the needle by azimuth, height and depth.

Abstract: A circular ultrasound transducer is divided into separate semi-circular transducer elements. Each element is separately operable, and each is aligned with similarly configured lens segments having different focal zones.

Abstract: Ultrasound breast scanning and diagnosis is achieved by suspending the breast in a water pool, in which is immersed a wide aperture transducer/lens assembly. The water path is defined by two separate segments, an upper one, into which the breast is suspended, contained by a flexible sonically transparent bag member, and the lower being contained in a longitudinally movable tank which is filled to contact with the bag member portion protruding into the tank.

Abstract: Images and respectively associated timing marks are arrayed, as phototransparencies, about a disk. The disk is rotated and the timing marks are sensed. Display occurs either in two-dimensional fashion, such as in a television system, or in three-dimensional fashion such as in a semitransparent full image projection. Associated logic circuitry determines whether the full 3-D transparency is to be produced, in which case all images on the disk are to be illuminated, or whether swim through will occur, either on an image at a time or on a "ham slice" projection basis.

Abstract: Electronic means, including an analog-to-digital converter responsive to samples of the output from an analog angle sensor directly coupled to an immersed oscillated transducer, is used to trigger the energization of the transducer at each of a predetermined number of equal increments in angle position during each cycle of oscillation of the transducer, with the triggered angle positions during a certain half-cycle of oscillation being interlaced with the triggered angle position during the other half-cycle of oscillation.

Abstract: Transducer completely immersed in ultrasonic propagating liquid can be oscillated back and forth at a high rate, without producing significant turbulence in liquid, if oscillation velocity varies as a predetermined smooth continuous function of time.

Abstract: A B-scan pulse echo ultrasound system produces a real time image of a body area under inquiry, and an aspiration needle is inserted directly into that area. The needle carries a small, omni-directional ultrasound transducer, electrically connected through the needle to transponder electronics. Incident pulses from the imaging transducer to the omni-directional transducer are sensed at the latter, and the position thereof is inserted into the image either by generation of a return signal from the needle point, or through delay logic and subsequent production of a composite.

Abstract: A lens assembly exhibiting a certain fixed relative aperture is comprised of a physical acoustic lens having a given physical aperture and a fixed relatively short focal length serially spaced from an electronic acoustic lens having any selected one of a plurality of different relatively long focal lengths and simultaneously controlling the physical aperture of the electronic acoustic lens such that the relative aperture of the assembly as a whole remains fixed regardless of the selected one of the long focal lengths. Such a lens assembly is suitable for use in a pulse-echo ultrasonic-imaging system for imaging a deep structure.

Abstract: A control pulse is generated whenever the instantaneous amplitude of an arbitrary-waveform input signal differs by a fixed increment from that of a preceding sample of the input signal. The input signal is resampled in response to the control pulse and the whole operation is repeated.

Abstract: Transducer completely immersed in ultrasonic propagating liquid can be oscillated back and forth at a high rate, without producing significant turbulence in liquid, if oscillation velocity varies as a predetermined smooth continuous function of time.

Abstract: A transducer comprising a longitudinal bar of piezoelectric material having one longitudinal face substantially covered with a first electrode and the opposite longitudinal face in contact with a predetermined plural number of separate electrodes spaced along the length thereof, permits all detected echoes to be processed by a single low input impedance amplifier permanently coupled to the first electrode.

Abstract: An ultrasonic transducing unit comprising a central section, which cooperates with only a small portion of the relatively large aperture of an acoustic lens, and an annular section, which cooperates with the remainder of the aperture, can be selectively operated by switch means to utilize the relatively large depth of focus detected signal of the central section alone or to utilize the relatively small depth of focus detected signal of both the central and annular sections together.

Abstract: An improvement to a pulse-echo ultrasonic-imaging system employing an acoustic focusing device occupying a fixed aperture to both illuminate internal structure of a visually opaque object with a scanning focused beam of ultrasonic energy and for returning a reflected signal portion of the scanning focused beam passed therethrough for detection. The improvement accomplishes real time scanning by scanning all of the image samples within a group of such samples in a time period not much longer, at most, than the round-trip travel time delay of the focused beam required to receive the reflected signal portion of only a single sample for detection. By way of example, this may be accomplished by a phased-array transducer arrangement.

Abstract: An acoustic focusing device occupying a fixed aperture is used to both illuminate internal structure of a visually opaque object with a scanning focused beam of ultrasonic energy and for returning a reflected signal portion of the scanning focused beam passed therethrough for detection. The use of such a fixed-aperture focusing device permits deep soft tissue of a living human being to be displayed with high resolution for medical diagnostic purposes in a manner compatible with a real time frame rate.

Abstract: An improvement to a pulse-echo ultrasonic-imaging system employing an acoustic focusing device occupying a fixed aperture to both illuminate internal structure of a visually opaque object with a scanning focused beam of ultrasonic energy and for returning a reflected signal portion of the scanning focused beam passed therethrough for detection. The improvement makes it possible to employ a large numerical aperture spherical lens exhibiting aberration as the focusing device by utilizing a corrector plate. The corrector plate causes the lens to image a flat transducer in a flat image field. Were it not for the corrector plate, the lens aberration would provide an undesired curved image field. The improved system is suitable for displaying deep soft tissue of a living human being for a medical diagnostic purpose.

Abstract: An improved pulse-echo ultrasonic-imaging system for scanning, in real time, objects such as soft tissue within a living human body. It employs a transducer including first and second parallel wave-energy generating electrodes extending linearly in a first direction and a linear array of image-spot detecting electrodes also extending in this first direction and is situated half-way between the first and second electrodes. Scanning in a second direction orthogonal to the first direction is provided by counter-rotating Risley prisms rotating at a predetermined rate. The distance between each of the first and second electrodes and the linear array is related to this predetermined rate such that reflected wave energy is always directed to the linear array.

Abstract: An improvement to a pulse-echo ultrasonic-imaging system, which permits the displaying of a three-dimensional representation of internal structure such as the soft tissue within the body of a living human being. The improved system includes a focusing device, such as an acoustic lens or an acoustic axicon, which provides a depth of field for the scanning focused beam which is several times the focused spot size of the scanning focused beam and which is at least as great as the depth dimension of the structure.

Abstract: A portable apparatus for measuring ultrasonic signal waves using interference between a reference reflected laser beam and one reflected from a gold-coated plastic film exposed to the sonic signal and located at the interface between liquids of different viscosity but which have substantially equal acoustic impedances. The liquids may respectively comprise water and fluorocarbon liquid.