Abstract: In an x-ray imaging system, an x-ray detector assembly includes an x-ray detector and a support assembly secured to the x-ray detector for supporting an antiscatter grid assembly. The x-ray detector preferably includes a matrix of crystal detectors. The support assembly includes a foam bezel having one or more magnets disposed therein. The antiscatter grid assembly includes an antiscatter grid secured to a metal frame. The one or more magnets disposed in the bezel are situated so as to align with the metal frame of the antiscatter grid assembly when the antiscatter grid assembly is coupled to the x-ray detector assembly. The strengths of the one or more magnets are such as to allow the antiscatter grid assembly to be removably secured to the x-ray detector assembly. Alternatively, the one or more magnets may be secured to the metal frame of the antiscatter grid assembly and corresponding metal plates may be placed in the support assembly.

Abstract: A gamma camera system includes two or more radiation detector heads and which are mounted opposite each other to a gantry for rotation about a subject. A transmission radiation source assembly is mounted to the front face of at least one of the detectors and can be moved across the face of the detector. The source assembly includes a radiation attenuating housing, a leaded bronze source holder, and a radionuclide source. The radionuclide source is retained in a longitudinal groove disposed in the source holder. The source holder may be rotated into open, closed, and access positions. The transmission radiation emitted by the source assembly is directed across the examination region, attenuated by the subject, and detected by the opposed detector. The gamma camera system also includes a filter which selectively attenuates the transmission radiation to obtain a desired attenuation profile which prevents saturation of the opposed detector.

Abstract: An x-ray tube includes an anode, a cathode, and an electrode disposed in an evacuated envelope. The electrode is positioned such that the electrode is remote from an area in immediate proximity to the envelope. An electric field defined by electrode is of sufficient strength such that arcing preferentially occurs between the electrode and the anode as opposed to occurring between the cathode and anode. The electrode is further situated such that metal sputtered from the electrode substantially falls in a define region on the anode and serves as an active getter for pumping gas from the envelope. The electrode is composed of an active metal which, upon being passively heated by the anode, also acts as a getter material to aid in pumping gas from the envelope.

Abstract: An x-ray tube is disposed within an x-ray tube housing defining a chamber filled with oil or other cooling medium for cooling the x-ray tube. The x-ray tube includes an envelope enclosing an evacuated chamber in which an anode assembly is rotatably mounted to a bearing assembly and interacts with a cathode assembly for production of x-rays. The bearing assembly includes a bearing housing and a plurality of bearings disposed on a surface of the bearing housing. A heat sink is coupled to the bearing assembly and provides a thermally conductive path between the bearing assembly and the cooling medium in the x-ray tube housing for providing direct cooling of the bearing assembly during operation.

Abstract: A tissue dispenser comprising a hollow container forms an inner chamber for housing a roll of tissue. The container comprises two separable housing components which when separated enable the insertion of rolled tissue into the chamber and when fitted together enclose and support the rolled tissue in the chamber. Each of the housing components are substantially identical. When fitted together, the housing components define the container walls and sides to surround the rolled tissue, an aperture through which the free end of the tissue is passed during dispensing and a spindle on which the rolled tissue is supported for dispensing. The tissue dispenser includes releasable mating means to releasably mate one housing component to the other to form the dispenser assembly.

Abstract: An x-ray tube includes an envelope defining an evacuated chamber in which an anode assembly is rotatably mounted to a bearing assembly and interacts with a cathode assembly for production of x-rays. The bearing assembly includes a bearing housing and a plurality of bearings disposed on an outer surface of the bearing housing. A cooling channel is defined within the bearing assembly and directs cooling fluid such as oil across an inner surface of the bearing housing. As the cooling fluid flows adjacent the inner surface of the bearing housing, heat from the bearing housing is absorbed by the cooling fluid thereby reducing the heat transferred to the bearings.

Abstract: An x-ray tube includes an envelope defining an evacuated chamber and having a window transmissive to x-rays. An anode assembly and a cathode assembly operate within the envelope to produce x-rays which travel through the window transmissive to x-rays towards a patient or subject under examination. A shield transmissive to x-rays is coupled to the envelope and positioned such that x-rays traveling through the window transmissive to x-rays must first travel through the shield. The shield prevents substantially all secondary electrons created during the production of x-rays from coming into contact with the window transmissive to x-rays thereby preventing excessive heating of the window transmissive to x-rays. An electrode defined by the envelope in a region proximate the window transmissive to x-rays may additionally or alternatively be used to prevent secondary electrons from reaching the window transmissive to x-rays.

Abstract: A microscope calibrator probe includes a handle, a tool head connected to the handle, a viewable target connected to an end of the tool head opposite the handle, and three or more position signaling devices disposed on the handle for tracking the probe in an image guided surgery system. The tool head includes a bend of approximately 90 degrees to provide easy placement of the viewable target on an object being viewed below a microscope. Other angles for the bend are also acceptable. A precise location of the object being viewed is determined by sensing a location the three or more position signaling devices disposed on the handle with respect to an operating room reference frame and knowing an offset between the position signaling devices and a bottom surface of the viewable target in contact with the object. Additionally, the viewable target includes a viewable aperture for calibrating a line of sight of the microscope and a means for indicating a rotational sense of the viewable target.

Abstract: An imaging apparatus includes a plurality of detector assemblies disposed for rotation about an imaging region. The detector assemblies may be adjusted between at least two relative angular orientations about the imaging region. The relative angular orientations are selected based on the size of an object within the imaging region. The center of the transverse fields of view of the detectors may be offset from the axis of rotation. Gamma radiation generated by positron annihilation events is detected and used to generate tomographic images.

Abstract: A tool calibrator includes two portions shaped to slidably engage and secure a tool in a desired position. The tool is secured by a series of staggered V shaped grooves on each of the two portions having a known geometrical relationship with a diameter of a tool head of the tool. The tool calibrator further includes at least one position signaling device for communicating a location of the tool calibrator in an operating room or other area. A position and direction of a tip of the tool is determined by comparing a location of the tool secured within the tool calibrator to the location of each of the two portions. Further, based on the location of each of the two portions, the diameter of the tool head is calculated.

Abstract: A rotating assembly 79 includes an anode assembly 55 coupled to a shaft 70 and a rotor 75 including a rotor body 77. The anode assembly 55 includes an elongated neck portion 58 and is rotated via the shaft 70 about an axis of rotation 65 in an x-ray tube 12. The shaft 70 is mounted by a straddle bearing assembly 68 having a bearing housing 100. The bearing housing 100 includes a first elongated portion 101 and second elongated portion 102, and a base portion 103. The first elongated portion 101 and the second elongated portion 102 each pass through a center of mass C of the rotating assembly 79 and define an cooling duct 119 for removing heat from the anode assembly 55 during operations. A first bearing 90a and a second bearing 90b are disposed in the bearing housing 100 on opposite sides of the center of mass C of the rotating assembly 79.

Abstract: An imaging apparatus includes a pair radiation sensitive detector heads disposed on opposite sides of the patient. The detectors and patient are moved relative to each other in an axial direction while the relative angular orientation of the detectors and the patient is held constant. Positron annihilation events occurring within the anatomy of a patient are detected and used to reconstruct an image. According to one reconstruction technique, a focal plane method is used. The intersections of the lines of coincidence and a plurality of image planes is determined, and a series of images indicative of the intersections is generated.

Abstract: A method and device for selectively displaying a magnified image which permits an operator to appreciate the magnified image in its original context. The device includes a main monitor, a magnifier monitor, associated memories, and a controller. The magnifier monitor is movably mounted with respect to the main monitor. The position of the magnifier monitor in two dimensions represents the approximate center of a region on the main monitor to be magnified. The magnifier monitor is movable in a third dimension, and the position of the magnifier in the third dimension is used to determine the degree of magnification desired.

Abstract: A tool or device for use in interventional MRI has a matrix of electrical conductors formed on or carried by the outer surface of the tool or device so that in use energisation of the conductors can be effect in order to enable the susceptibility of the tool or device to be varied and thus the apparent shape of the tool or device to be varied.

Abstract: An MR imaging apparatus includes a magnet assembly having two generally opposed pole pieces. Current flowing in driver coils associated with each pole pieces generates a magnetic field in the imaging region. The driver coils include a conductor having beveled edges, the conductor being wound in a spiral fashion. A layer of electrical insulation is located between the conductor windings. A cooling member fabricated from bifilar wound tubing having a generally rectangular cross section is in thermal communication with each driver coil. Coolant flowing through the cooling member removes heat generated in the driver coils.

Abstract: A transformable gamma camera includes detectors mounted for circumferential movement with respect to a rotating gantry. The rotating gantry includes radial bores at desired angular positions about the rotating gantry. The stationary gantry includes a docking station such as a bore. A coupling mechanism allows the detectors to be coupled to the bores in the rotating gantry or to the docking station. Each of the detectors is movable radially with respect to the rotating gantry's axis of rotation and tangentially to the imaging region. The gamma camera is readily transformable between 120 degree, orthogonal, and opposed detector configurations; a plurality of aperture sizes can also be defined.

Abstract: In magnetic resonance imaging (MRI) apparatus in which weight considerations and accessibility of the patient result in a magnet 1 with a large bore 2, in order to enable spectroscopy or other activities requiring large magnetic fields to nevertheless be carried out, a small magnet 4 with its own cryostat can be moved from an inoperative position A to an operative position B, in which the large magnet acts as a shield winding for the small magnet.

Abstract: A nuclear camera system includes oppositely disposed radiation detectors (10a, 10b) which view an examination region 14 wherein a subject 16 is received therein. During a diagnostic scan, a motor and drive assembly (18) concurrently moves the detectors (10a, 10b) in a straight path along a longitudinal axis (20) for a selected time interval. The radiation detectors (10a, 10b) are positioned at a first angle at which the subject is viewed and the angle is maintained through the scan. A data processor (23) collects the data from the detected radiation and a coincidence circuitry (26) determines coincidence radiation events occurring on the detectors 10a, 10b. A first set of image data is generated for the first angular view and stored in a view memory (28). A second scan is performed where the detectors (10a, 10b) are shifted to a second angular view and the detectors are moved along the longitudinal axis for a second selected time interval.

Abstract: A surgical guide for use with an image guided surgery includes first and second surfaces. At least three signaling devices such as infrared emitters are disposed on the first surface, and a cylindrical mounting boss is disposed on the second surface. A guide aperture is perpendicular to the first and second surfaces and extends between them. The guide aperture is configured to support a surgical tool such as a biopsy needle. A sleeve may be placed in the aperture to support additional tools.

Abstract: A magnetic probe (1) for use with a magnetic resonance imaging apparatus comprises an electron spin resonance (ESR) magnetometer. The position of the probe (1) tracked by measuring the resonant frequency of an ESR sample (32) in the probe. The resonant frequency is measured in the presence of a gradient sequence which employs three orthogonal, linear gradients. By determining the resonant frequency of the ESR sample in the presence of each of the gradients, the position of the probe can be determined. The probe may be placed on or in an object, and the position of the probe may be displayed on a desired magnetic resonance image of the object.