Abstract: A calculi locator is provided having at least one ultrasound transducers in combination with a shock wave generator. The ultrasound transducer is rotatable about the longitudinal axis of a reflector of the shock wave generator. The shock wave generator includes a target focal point. The transducer is used to assure positional coincidence of the true location of the calculi and of the target focal point. Alternatively, either a mathematical correction unit is used or iterative measurements are used to correct for refraction errors in the location of the imaged calculi.

Abstract: A calculi locator is provided using an ultrasound transducer in combination with shock wave generator. Various means are provided for assuring coincidence of ultrasound obtained images of the calculi, the actual location of the calculi and of the target focal point of the shock wave generator means.

Abstract: In-vivo bone density measuring system using a modified emission computed tomographic gamma camera arrangement for detecting radiation from two separate sources located outside of the body of the patient and oppositely disposed to the gamma camera during rotation of the gamma camera and sources means about the patient for obtaining tomographic data. The two separate sources emitting at least two energy levels. The system includes processing means for the detected radiation to provide a bone mineral density map.

Abstract: Time gain compensation is provided on an automatic basis by storing an amplification gain function for an amplifier operating on the received signals and automatically varying the function until the intensity versus time functions of the received signal is substantially flat.

Abstract: An X-ray mammographic biopsy needle holder positioning system wherein the X-ray source is tilted to provide parallax views of the needle holder inserted in the breast. The tilting occurs independently of the breast compressor which remains untilted.

Abstract: A multi-transducer ultrasound probe including a housing having an ultrasound window with a torquer driven pulley system for positioning and oscillating a selected one of the multi-transducers in the window while activating the selected transducer.

Abstract: An electronic multi-imaging system displays medical images obtained from scans of a patient, and stored in a digital memory, on the screen of a TV monitor. The medical images occupy different spatial locations on the screen and do not overlap. An optical system operatively associated with the screen focuses an image of the screen onto a sheet of photosensitive material such that each of the medical images occupies only a portion of the sheet at predetermined spatial locations that are functionally related to the predetermined spatial locations of the medical images on the screen of the TV monitor.

Abstract: A digital fluorographic system for displaying images comprising video and multi format display means which are each provided image data from large size matrices (1024.times.1024). The data is compressed and is provided to the video display at speeds that preclude the necessity of using broad bandwidth equipment.

Abstract: A map of a radiation field produced by a gamma camera is corrected for three types of spatially dependent errors in a manner that corrects for each error independently of the others. The errors corrected for are dislocations which result from the non-linearity of the optics, photomultipliers and electronics of the camera, energy window variations resulting from inhomogeneity of the optical system which includes the crystal, light guide, and photomultipliers, and the non-uniform sensitivity of the head resulting from the non-uniform stopping power of the crystal and collimator of the camera head. The map is corrected by obtaining a set of correction factors associated with each type of error using a calibration technique that insures independence between the various correction factors, and applying the correction factors to the map obtained in a nuclear imaging process in a way that independently corrects the map for each type of error.

Abstract: A method for using a gamma camera having a head including an array of photodetectors that produces a group of input pulses in response to an actual interaction of a radiation stimulus with the camera head, includes the step of repetitiously generating groups of synthetic pulses that resemble groups of input pulses and simulate the occurrence of synthetic interactions of stimuli with the head. These groups of synthetic and input pulses are applied to processing circuitry that produces groups of processed pulses. The coordinates of both actual and synthetic interactions based on said processed pulses are computed; and a representation of the spatial locations of both actual and synthetic interactions based on the computed coordinates is stored.

Abstract: A gamma camera has a scintillation medium responsive to radiation stimuli for producing an exponentially decaying scintillation at a location where a radiation stimulus interacts with the medium; a photodetector system responsive to a scintillation for producing outputs; and computation circuitry responsive to such outputs for producing intrinsic signals which have the same temporal nature as a scintillation and which are processed to produce coordinate signals representative of the coordinates of the scintillation producing such outputs. The computation circuitry includes truncation circuitry for electronically shortening the duration of intrinsic signals so that the computation circuitry effectively operates with signals of shorter duration than the scintillations.

Abstract: By reason of the nature of the scanning regimen followed by a scanning gamma camera head, and the shape of the active region of the head, not all of the elemental areas of a scanned radiation field are observed by the active region of the head for the same period of time. This non-uniformity sensitivity of the system is corrected by correction factors that are either analytically calculated or experimentally determined for each given elemental area of the map. The map of an unknown radiation source obtained by following the scanning regimen is corrected by applying the sensitivity correction factors to the contents of corresponding elemental areas of the map.

Abstract: The intensity distribution of a radiation field imaged on a scintillation crystal of a gamma camera can be quantified by assigning to each elemental area of the crystal, a number representing the number of light events calculated to have occurred in the given elemental area within a predetermined period of time. The resolution of the camera is improved by weighting the contents of the elements in the memory in accordance with the probability that an event, calculated to have occurred in a given elemental area, actually occurred therein, such that the weighted contents of the memory more closely approaches the actual density distribution of light events as compared to the unweighted contents of the memory.

Abstract: A map of a radiation field produced by a gamma camera is corrected for three types of spatially dependent errors in a manner that corrects for each error independently of the others. The errors corrected for are dislocations which result from the non-linearity of the optics, photomultipliers and electronics of the camera, energy window variations resulting from inhomogeneity of the optical system which includes the crystal, light guide, and photomultipliers, and the non-uniform sensitivity of the head resulting from the non-uniform stopping power of the crystal and collimator of the camera head. The map is corrected by obtaining a set of correction factors associated with each type of error using a calibration technique that insures independence between the various correction factors, and applying the correction factors to the map obtained in a nuclear imaging process in a way that independently corrects the map for each type of error.

Abstract: The dead time of a nuclear imaging system is compensated for when recording a representation of a dynamically changing radiation field into an image memory by injecting into the system synthetic pulses which resemble, in terms of amplitude and shape, the pulses produced by the system in response to interaction with stimuli from the radiation field, and by determining the percentage of synthetic pulses which are processed by the system. A correction factor based on such percentage is applied to the representation of the field. The synthetic pulses are injected into the system at a predetermined rate with respect to the rate of pulses processed by the system in response to interactions with stimuli from the radiation field. This predetermined rate is functionally related to the rate at which input signals are processed by the system.

Abstract: A fan beam of the type described herein is oriented so as to be coplanar with the cross-section of a body to be reconstructed. Pure rotational movement is imparted to the fan beam by rotating the same about a fixed center of rotation such that the fan beam sweeps out an area in the plane of the cross-section; and the absorption coefficients over such area can be computed in a known manner from measurements of the intensities of the beams emerging from the area swept out thereby.When one extremity of the fan beam passes through the fixed center of rotation, the area swept-out by the fan beam during one revolution thereof is circular, the center of which is coincident with the fixed center and the periphery of which is tangent to the other extremity of the fan beam. When the fixed center lies outside the fan beam, the area swept-out is annular and is defined by concentric circles whose centers are coincident with the fixed center and whose peripheries are respectively tangent to the extremities of the fan beam.

Abstract: Light coupling means interposed between the photosensitive surfaces of an array of photodetectors and a scintillation crystal has a recess associated with at least one of the photodetectors, the recess being located in the light coupling means within the volumetric projection of the photosensitive surface of said at least one of the photodetectors. The recess is filled with material having an index of refraction different from the index of refraction of the light coupling means such that the index, throughout the recess, is uniform. The provision of the material with a different index in the recess serves to alter the direction of light from a light event in the crystal as the light passes through the light coupling means thereby modifying the relative amount of light received by each of the photodetectors of the array, and thereby improving spatial linearity, uniformity and resolution.

Abstract: Radiation imaging apparatus includes a scintillation crystal responsive to radiation stimuli for producing light events, and a plurality of photodetectors arranged in a predetermined array relative to the crystal, each of the photodetectors having a light-sensitive surface facing the crystal and being responsive to a light event for producing an output signal. Coupling means associated with each photodetector applies its output signal to coordinate computing circuitry which computes the coordinates of a light event from signals applied thereto.In one embodiment of the invention, at least one of the coupling means includes a threshold linear gate for applying the output of the photodetector with which the coupling means is associated, to the coordinate computation circuitry only if the input to this particular photodetector exceeds a predetermined threshold.

Abstract: Coordinates of a light event, computed by signal processing equipment from output signals developed by an array of photodetectors of radiation imaging apparatus in response to the interaction of a radiation stimulus with a scintillation crystal, are validated only if a representation of the total energy of the light event lies within an energy window functionally related to the coordinates of the light event. In this manner, only desirable radiation stimuli interacting with the crystal are detected, and undesirable, indirect or scattered radiation stimuli interacting with the crystal are discriminated against.

Abstract: A cell analyzer which automatically processes and evaluates cell samples for possible indications of malignancy and other abnormalities is disclosed. Cell samples are prepared in a suspension and are tagged with an appropriate radioactive stain or appropriate biochemical. Counting, filtering and drying steps under computer control are followed by the taking of a radioactive count with respect to a normalized number of cells. The results of the radioactive counting determine whether the particular sample is classified as "positive" or "negative".