Abstract: A superconducting magnetic imaging apparatus includes a vacuum vessel (16) having a central helium reservoir (20) in which superconducting magnetic coil windings (12) are maintained at a superconducting temperature. The vacuum vessel defines an internal bore (22) within which a self-shielded gradient coil assembly (26) and an RF coil (30) are received. The self-shielded coil assembly includes a single former (50) which defines an imaging region (14) within which an imaged portion of a subject is received. Primary x, y, and z-gradient coils (72-76) are positioned over an RF ground screen (70) that is bonded to the former (50). A number of comb-like spacers (84) extend from the former to supporting shield x, y, and z-gradient coils (110-114). The comb-like spacers define passages between the primary and secondary gradient coils which receive inner and outer cooling tubes (90, 92) and shim tray molds (108). The fully assembled gradient coil assembly is potted to form a unitary structure in a single potting step.

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 magnetic resonance imaging apparatus includes a main magnet (12) for generating a main magnetic field in an examination region (14) and a radio frequency coil assembly. The radio frequency coil assembly transmits radio frequency pulses into the examination region (14) to induce magnetic resonance in selected dipoles disposed therein. The radio frequency coil assembly also receives signals from selected resonating dipoles. The radio frequency coil assembly includes a birdcage coil (60) having a plurality of conductive elements (64) constructed on a dielectric form positioned about the examination region (14). The birdcage coil (60) includes a plurality of capacitors (C1-C24) and corresponding plurality of series connected diode inductor pairs connected in parallel with each capacitor to form resonant trap circuits.

Abstract: A snap-in, whole-body radio frequency coil (38) for increasing the diameter of a bore (12) of a toroidal magnetic resonance imaging apparatus includes a plurality of longitudinally extending coil elements (42) having element ends (44). The longitudinally extending coil elements are disposed on a flat, flexible, non-conductive plastic sheet (40) which is capable of being rolled and disposed concentricly in an interior diameter of the bore to form a thin-walled, bird-cage type radio frequency coil. Adjacent element ends are connected with a first capacitance C.sub.0 to resonate the coil at a certain frequency. To permit mechanically switching the resonant frequency of the coil, protruding metal contacts (60) are electrically connected to the element ends. An adjustment end ring includes separated metal pads (66) disposed on a non-conducting ring substrate (64). Adjacent metal pads are connected with second capacitances C.sub.1.

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 versatile patient support and restraint system is provided. It includes a couch (14) having a top surface (22) for supporting a patient being examined within an examination region (12). Two substantially parallel grooves (20) are formed along a longitudinal direction in the top surface (22) of the couch (14) on opposite sides thereof. Two removable tracks (30) extending in a longitudinal direction are removably seated in the grooves (20). Adjustable restraint straps for securing the patient to the couch (14) are also provided. The adjustable restraint straps include pins attached to opposing ends of the adjustable restraint straps. The pins selectively engage the two removable tracks (30) thereby selectively securing opposing ends of the adjustable restraint straps to opposite sides of the top surface (22) of the couch (14).

Abstract: A position signaling is usable in connection with an image guided surgery system. A plurality of infrared emitters are mounted on a reference object. The reference object is in turn attached to the rocker arm of a head clamp. The head clamp includes a frame and a first head engaging pin secured to one side of the frame. The rocker arm includes two head engaging pins and is movable in relation to the frame. The image guided surgery system uses the signals provided by the infrared emitters to determine and account for movement of the patient's head.

Abstract: A forward projector/backprojector (30) for a CT scanner (10) includes a VME interface (36) which loads data onto and off of the forward projector/backprojector (30), and a CPU (42) which controls data flow. An array of ASICs (60a-x) is included. Each ASIC has two pipelines along which data is subjected to pipeline operations including one of a forward projection algorithm and a backprojection algorithm. Double-buffered memories for storing data subject to the pipeline operations are arranged on each ASIC (60a-x) such that while data is loaded into one bank of the double-buffered memories data in its opposing bank is subject to pipeline operations. A dual in-line memory module (DIMM) daughtercard (120) holds an output memory (100) with two banks employed during pipeline operations.

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: A high voltage power supply includes a high voltage high frequency generator (10) having outputs (12, 14). An arc limiting device (20) is connected in series to the outputs (12, 14) of the generator (10). The arc limiting device (20) includes two coils (22, 24) of a wound length of wire (50) that exhibit a skin effect. The skin effect forces higher frequency current components to flow at a surface of the wire (50) through a limited skin layer portion (62) of a cross section of the wire (50). In one preferred embodiment, the arc limiting device (20) is connected via high voltage cables (32, 34) with an x-ray tube (40). Suitable material for the wire (50) includes those materials with high permeability to resistivity ratios, for example iron, purified iron, 78 permalloy, 4-97 permalloy, mu metal, or supermalloy.

Abstract: A radiographic scanner (10) has a stationary gantry portion (12) defining a subject receiving region (16) and a rotating gantry portion (20) on which an imaging x-ray tube (22) is mounted. The rotating gantry portion (20) is rotatably mounted to the stationary gantry portion (12) for rotation about the subject receiving region (16). A slip ring assembly extending around the subject receiving region (16) connected with the stationary and rotating gantry portions, includes a scintillating optical fiber (44) mounted around the patient receiving region (16) to one of the rotating and stationary gantry portions. A communication x-ray tube (40) is mounted to the other gantry portion and directed such that radiation therefrom enters the scintillating optical fiber (44) from a lateral direction. The scintillating optical fiber (44) converts the incident x-rays (52) to light (58) and transmits the light (58) along its longitudinal axis.

Abstract: A magnetic resonance imaging apparatus (10) has a main magnet having a pair of pole faces (16,18) defining an examination region (14). The main magnet generates a main magnetic field (12). A couch (30) suspends a subject within the examination region (14). A uniplanar gradient coil assembly (40) is positioned to one side of the subject. The uniplanar gradient coil assembly (40) generates magnetic field gradients across the examination region (14). The uniplanar gradient coil assembly (40) includes coil loop arrays each residing in a plane which is transverse to the main magnetic field (12). A current supply (42) supplies a electrical current pulses to the coil loop arrays. A radio frequency pulse generator (50) is employed for selectively exciting magnetic resonance of dipoles within the examination region (14). A receiver (54) receives magnetic resonance signals from the resonating dipoles and a reconstruction processor (62) forms an image representation from the magnetic resonance signals received.

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 stereotactic guide apparatus 100 is provided for use with a CT scanner device 18 for guiding the entry of a probe into a patient's body. The CT scanner device is provided with a stereotactic arm member 30 having a first base end 42 connected to the CT scanner device 18 and a second free end 40 movable relative to the CT scanner device. The stereotactic surgical instrument guide apparatus includes a first end effector member 106 including a guide channel 152 defining a probe insertion path 150. The surgical instrument guidance device further includes a second end effector member 104 on the free end of the stereotactic arm member and including a laser light source 108 generating a light guide beam along the probe insertion path 150.

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 gantry (A) has a bore defining a first patient examination region (12). A first x-ray source (B) is mounted to a frame (C) for rotation around the examination region (12). An arc of first radiation detectors (14) detects x-rays which have traversed the examination region. A first image reconstruction processor (18) reconstructs a tomographic image representation from signals generated by the first radiation detectors. An angiographic device (D) is positioned remote from the gantry along a longitudinal axis (25) for generating and displaying angiographic image representations on a display monitor (46). A second examination region is defined along the longitudinal axis (25) between a second x-ray source (36) and an image intensifier tube (38). A second processor (44) reconstructs the angiographic projection image representations from signals generated by the image intensifier tube (38).

Abstract: A magnetic resonance imaging apparatus (10) includes a primary magnet assembly for generating a temporarily constant magnetic field through an examination region (20), a gradient coil assembly for inducing magnetic field gradients across the examination region (20), and a radio frequency coil for receiving resonance signals from the examination region. The gradient coil assembly includes a coil carrying member (22) carrying first (44) and second (46) spaced apart gradient coil portions which are physically separated from each other on the coil carrying member to define at least one azimuthally directed gap (48, 50, 52, 54) extending along the coil carrying member between said first and second gradient coil portions. The first and second coil portions are disposed towards opposite top and bottom sides of the examination region and have internal windings therein for generating gradient magnetic field components along at least two mutually orthogonal axes (X, Y) in the examination region.