Abstract: Proximity controls for controlling the proximity of a gamma camera to a patient during a scan of the patient. The proximity controls consist of two spaced apart energy screens, each comprising 200 beams, parallel to and spaced from the detector of the gamma camera. When neither screen is interrupted, the camera is moved towards the patient. When both screens are interrupted, the camera is moved away from the patient. When only the screen farthest from the detector is interrupted, the camera is braked so as not to move away from or towards the patient.

Abstract: A system for controlling the scan limits of a gamma camera during a whole body scan regimen wherein the limits are set by controls at the patient bed.

Abstract: A gamma camera that iteratively determines corrected X, Y coordinate locations of events based on optimizing an event location function for each PM using the distance between the event and the PM's.

Abstract: A system for recording fewer of the events that are caused by unwanted photons with greater stability. The system locally determines the energy spectrum and fits for each pixel of the image the determined energy spectrum with a modified trial function composed of: a photopeak component of known energy shape, Compton scatter components having theoretically derived energy shapes and, when applicable, also measured or calculated energy spectra of other unwanted photons. The modified trial function also takes into consideration unknown local deviations in the outputs of electronic components. The amplitude of the photopeak distribution resulting from the fit is used to obtain the local content of wanted interactions in the image. This enables removal of Compton contamination and also the contamination caused by interaction of the gamma photons with lead components.

Abstract: A system for recording fewer of the events that are caused either by Compton scatter photons or by gamma radiation interacting with lead. The system locally determines the energy spectrum and fits the determined energy spectrum with a trial function composed of a photopeak component of known energy shape, but unknown magnitude and a Compton scatter component having a theoretically derived energy shape and an unknown magnitude for each pixel of the image. The trial function is locally fitted to the measured energy spectrum to obtain the values of both the Compton Coefficient and the gamma radiation interacting with lead. This enables removal of Compton contamination and also the contamination caused by interaction of the gamma photons with lead components.

Abstract: A system for simultaneous, real time imaging of biological tissue and measuring of blood flow velocities using the Doppler principle resulting in an improvement in Doppler power spectrum of the blood flow velocity measurements.

Abstract: An automatic windowing system for ultrasonic imaging wherein the incoming signal is separated into a high spatial frequency component and a low spatial frequency component. A comparatively low ratio of compression is applied to the high spatial frequency component while a high ratio of compression is applied to the low spatial frequency component. The two components after compression are added to form the signal used for display.

Abstract: A system that enables the communication of data and control signals between the rotor and the stator of a gantry using light transmitters and light receivers. The transmitters are attached to the gantry is such a manner that the light beams are transmitted in a direction that traverses the radial direction of the rotor of the gantry and also traverses a line parallel to the axis of rotation of the rotor. Further, the light beam from the transmitter to the receiver is shaped to minimize the dynamic range of the light flux variation. The light beams from transmitter to receiver are substantially direct line of sight beams and are not reflected through any light channels or carried in any optical transmitting means such as fibre glass.

Abstract: A magnetic resonance imaging system that:applies gradient pulses in a sequence that elicits large amounts of data early in a scan to provide an evolving image; and reduces the Gibbs artifacts to increase the utility of the evolving images.

Abstract: Correction for Compton scattering is effected by analysis of the energy spectra. More particularly, a measured energy spectrum is constructed per location from detected counts that are stored according to their measured energy as well as according to the location of gamma ray infingement on a scintillating detector. The measured spectrum comprises scattered and unscattered photons. A physically correct trial function enables the separation of overlapping contributions of scattered and unscattered photons. The trial function includes multiple collision terms that are preferably constructed using the Nishina-Klein equations describing photon Compton scatter probability distributions. The count of unscattered photons per location is derived from the measured spectrum by locally fitting to the trial function. The count of the unscattered photons per location is used to produce the improved images with reduced artifacts caused by Compton scatter.

Abstract: A support rod for supporting structures in a cryostat of a magnetic resonance system. The support rod has oppositely disposed stainless steel heads mounted on a glass reinforced plastic rod. The heads have threads on the main body thereof to minimize the length of the heads and thereby minimize heat condition.

Abstract: Elimination of truncation artifacts in Magnetic Resonance Images is accomplished by analaytically optimizing controllable parameters; i.e., filter characteristic and assymetry ratio when asymetrically sampling arid time domain filtering followed by complex conjugating the filtered data to reduce the Gibbs artifact.

Abstract: A system for decoupling the body coil of the magnetic resonance imaging system when surface coils are used, and especially when the surface coils are used only for receiving. Semi-conductor switches; i.e., diodes are used in the body coil to decouple the body coils. However, gradient generated transients often erroneously switch off the diodes which are then destroyed by a subsequent transmitted RF signal. The invention provides fail safe circuitry for preventing RF transmission when the diode switches are in the non-conducting condition.

Abstract: A CT scanner using a rotate-rotate mode wherein the detector is designed to simultaneously detect X-rays that have traversed multiple-planar sections in a patient being scanned.

Abstract: A mammalary biopsy needle positioning scheme that improves on the system of U.S. Pat. No. 4,821,727. In the present invention, the arrival of the needle holder into a pixel is distinguished by comparing latest data per pixel to average data per pixel. If the comparison reveals marked differences from the average value, then the average value is discarded and the new data is used whereas in the absence of marked differences, the new data is averaged with the old average. The result is images with highlighted needle holder insertion information thereby providing images of the needle holder in the breast in a much shorter time than provided by the prior art and/or with smaller X-ray doses.

Abstract: A quadrature surface coil array comprising a plurality of single loop surface coils interspersed with a plurality of adjacent double loop surface coils, at least some of said surface coils overlapping the ends of adjacent surface coils and said double loop surface coils having the two loops in series to support only a single current mode thereby inhibiting cross coupling including next nearest neighbor cross coupling.

Abstract: A three dimensional imaging sequence that enables reconstruction during acquisition by acquiring all data required for imaging a plane perpendicular to the imaging plane and repeating for all such planes making up the three dimensional image.

Abstract: Receiver circuitry for a surface coil array used in magnetic resonance diagnostic systems, said circuitry minimizes reflections and thus relaxes the prior art necessity for balancing the individual receiver channel for each array by obtaining quadrature signals from the acquired signals in processing circuitry located as close as possible process-wise to the display equipment.

Abstract: An optical communication link coupling a rotating part of a gantry of a computerized tomographic scanner to the stationary part of the gantry. The link comprises an arcuate hollow light conductor having one part rotating with the rotor of the gantry and the other part fixed to the stator of the gantry. Signal bearing light beams are transmitted into the link and are subsequently received from the link after transversing at least a portion theroef.

Abstract: Obtaining data from a plurality of slabs in a volume of interest by using pairs of 90.degree. pulses with individual gradient pulses for presaturating volumes not of interest in the subject and subsequently selecting slabs in the volume of interest with RF pulses and slice-selecting gradient pulses.