Abstract: A method and coil arrangement for use in magnetic resonance imaging facilitates the examination of a localized region of the body. A plurality of substantially identical saddle coils are disposed about a former. The coils, which define a generally cylindrical volume, overlap one another in a circumferential direction. In one embodiment, a generally planar rectangular coil intersects the cylindrical volume. The method and coil arrangement are particularly well suited to imaging a region adjacent but outside the cylindrical volume. The coil arrangement is also well suited to insertion within the body, especially the rectum.

Abstract: A detector assembly for x-ray image acquisition includes a flat panel detector array. The detector assembly also includes a rechargeable battery, an analog to digital converter, and an image memory. The battery provides electrical power to the detector assembly so that image data may be acquired without using a power source external to the assembly. The image data is stored in a memory. The detector is subsequently be connected to a docking station which includes a battery charger. The image data is downloaded, and the battery is recharged.

Abstract: An MR compatible endoscope 1 has associated MR saddle coil 10 mounted on a removeable former 9. The tip 2 of the endoscope has the usual service channels for imaging. The coil 10 provides an additional MR signal. To avoid the need to plug the coil 10 in, it is inductively couples to a pick-up coil 13 and, to enable this to be removable as will from the endoscope, this may be located in one of the service channels 7 of the endoscope. The removable nature of the coil permits easy repair and, more importantly, a range of coils to be fitted to the endoscope to accommodate different magnetic field strengths.

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 based on the attenuation profile of the object so as to prevent saturation of the opposed detector.

Abstract: Radiation from a subject (18) which is received by a scintillation crystal (12) interacts with the scintillation crystal to produce a burst of scintillation light photons. The depth distribution at which the interaction occurs varies in accordance with the energy of the received radiation. Low-energy radiation tends to interact at a shallow depth relative to a front face of the scintillation crystal and radiation with a high energy tends to interact relatively deeply into the crystal. A moment processor (20) processes electronic information from photomultiplier tubes (14) which view the scintillation crystal to generate zero-th moment or energy information, first moment or coordinate information and second moment or depth information. The event information is filtered (34, 62, 66, 82) in accordance with depth (26), e.g., sorted into acceptable/unacceptable information, information corresponding to each of two or more energies of radiation, and the like.

Abstract: A camera for use in coincidence imaging includes detectors (10a, 10b) disposed about an examination region (12). Coincidence logic (14) determines whether gamma rays are detected by each of the detectors (10a, 10b) occur within a specified time interval. If so, the energy and positions of the detected events are determined. Energy discrimination circuitry (20a, 20b) associated with each detector (10a, 10b) determines if the detected events fall within a specified energy window. A list mode processor (22) generates a list of coincidence events. A rebinning processor (24) rebins the events, and a weight processor (26) weights each coincidence event based on the energy of the detected gamma rays.

Abstract: A marker and probe for use in magnetic resonance imaging includes a vial for insertion within the body. The vial contains a material having a spin-lattice relaxation time less than that of the material of the body in a region being imaged. A coil arrangement having at least one coil tuned to the frequency of the magnetic resonance excited in the material during an excitation sequence is wound around the vial. The body is subjected to an T1 weighted examination sequence. The coil arrangement preferably has at least one turn which lies in a plane orthogonal to at least one other turn. Materials suitable for use in the vial include copper sulphate, iron chloride, or gadoliuium cholate. The vial consists of a material which does not exhibit a nuclear magnetic resonance spectrum.

Abstract: A magnetic resonance imaging system includes a magnet system which includes pole pieces and an energizing coil. The end portions of the pole pieces are made from a material which, does not support eddy currents, such as insulated iron powder. An object to be imaged is placed in the gap between the pole pieces. A gradient coil system imposes desired gradient fields in the gap between the pole pieces. The gradient magnetic field sequences are controlled such that, for each gradient pulse or a particular polarity there is applied a compensating pulse of the same magnitude, but the opposite polarity. Each compensating gradient has an integral which is relatively small. Remanent magnetism in the end portions of the pole pieces is thereby substantially avoided.

Abstract: A gamma camera and a counterweight are mounted to a support structure. A motor causes the support structure to move about a pivot axis. A controller measures the rate of motion of the support structure and compares that rate to a predetermined rate. The controller causes a second motor to move the counterweight a distance based on the difference between the measured and predetermined rates. The process is repeated until the difference is less than a threshold value. In a second embodiment, the current drawn by the motor is measured. The controller causes the counterweight to move a distance based on the measured current. The support structure is rotated about an axis of rotation to a 90 degree position prior to moving the support structure and to a 0 degree position prior to moving the counterweight.

Abstract: Radiation indicative of an object being imaged is detected and a data set indicative of the detected radiation is generated. Negative cells within the data set are located and ordered for processing. A negative cell is selected for processing. A mask region is defined in relation to the selected cell, and positive cells within the mask region are identified. A correction factor is determined, the value of the positive cells is adjusted accordingly. The value of the selected cell is also adjusted so that the count value of the data set remains constant. If the value of the selected cell is still negative, new correction factors are determined and the values of the positive cells and the selected cell are again adjusted. The process is repeated until all of the negative cells within the data set have been processed. An image indicative of the object is then generated.

Abstract: A method of scatter correction for use with gamma cameras includes the steps of detecting and producing a first count value indicative of gamma radiation falling within a first energy range generally associated with a radionuclide photopeak. Gamma radiation falling within second and third energy ranges is also detected and a corresponding count produced. The second and third ranges are above and below the photopeak, respectively. The location of the second and third energy ranges is determined based on the energy resolution of the gamma camera such that a predetermined percentage of the radiation falling within the second and third ranges results from primary radiation. The second and third energy ranges may be located such that they are non-contiguous with the first energy range. Based on the count of radiation falling within the second and third ranges, the scatter radiation falling within the first energy range can be estimated, and the first count value corrected.

Abstract: Granulated bismuth is mixed with a liquid carrier into a suspension. The carrier - bismuth combination is applied to a surface in a thickness sufficient to provide a desired amount of radiation attenuation. The carrier adheres to the surface and maintains the bismuth adjacent said surface.

Abstract: An x-ray beam limiter includes a compressible disc 18 containing an aperture 20 and a slot 22 extending from the aperture to the outer edge 28 of the disc. The outer edge 28 of the disc 18 is covered with a bearing material and is retained within a groove 36 in a bearing retaining race 32 such that the disc 18 is rotatable within the retaining race 32. A beam limiter 54 is mounted to the disc 18. The disc 18 and beam limiter 54 are rotatable between at least two different positions.

Abstract: Current supply for MRI magnet having an output impedance which has been tailored to have the desired shape by using voltage and current feedback. The impedance is small at frequencies which are large with respect to the magnet L/R and the impedance is large at very low frequencies.

Abstract: In a magnet system, e.g. for use in a magnetic resonance apparatus, wherein a magnetic field is produced in a gap between pole pieces (5) joined by a yoke (7) by an electric drive coil arrangement carried on the yoke, stabilisation against variations in the field in the gap is provided by a stabilising arrangement (43) wherein over a section of its length the yoke is divided into a plurality of discrete parallel finger-like portions (45) each of which is surrounded by a separate ring (47) of superconducting non-magnetic material.

Abstract: A object handling system is moveable between various diagnostic imaging apparatus for imaging thereby. The handling system has an object handling computer 34 for storing object identification data and imaging data. Selectively linking the object handling computer 34 with a first imaging system provides the first imaging system with access to the object identification data and imaging data for use in the production of diagnostic images thereby. Similarly, the object identification data and imaging data are available to a second imaging system for use in the production of diagnostic images thereby when the object handling computer 34 is selectively linked thereto. The object identification data is associated with the diagnostic images produced by various imaging system for subsequent correlation of the object with the diagnostic images of the object.

Abstract: A radio frequency signal detector coil arrangement (17) for a magnetic resonance apparatus comprising a planar coil (25) and an annular magnetic flux rejecting arrangement (25) disposed coaxially with the planar coil, on one side thereof, which reduces the sensitivity of the planar coil to signals from sources remote from the axis of the planar coil. One embodiment of the flux reducing arrangement comprises an annular superconducting member (35) disposed between the planar coil and the body (31). In other embodiments it comprises an arrangement of coils which conform to a tubular surface coaxial with the planar coil, and electrically connected therewith.

Abstract: An image intensifier 18 is comprised of an evacuated chamber, an input surface 16 having a florescent material thereon for converting incident radiation into a visible light representative of the incident radiation, a photocathode layer 20 disposed closely adjacent the input surface for emitting a cloud of free electrons 22 into the evacuated chamber in proportion to the intensity of visible light at each point thereon, and an output surface 26 having a scintillating material thereon for converting electrons impinging thereon into a relatively bright light image proportional to the electron energy at each point on the output surface said light image having a first aspect ratio. An electrical potential 24 accelerates the free electrons from the photo-cathode to the output surface. A fiber optic bundle 28 comprised of an input face, positioned outside the chamber to view the bright light image at the output surface, and an output face 34 is provided.

Abstract: A radiographic imaging system is comprised of a radiation source 12, a radiation adsorbing grid assembly 18, an image producing element 22 a controller 34, an exposure sequence start means 28 and a grid assembly oscillation means 20. The radiation source and grid define a subject receiving gap, wherein an object under examination is disposed, and through which the source propagates a beam of radiation onto the face of the image producing element. The controller recognizes when the exposure sequence start means is activated and starts the exposure sequence. The exposure sequence is comprised of an exposure preparation interval and an exposure interval. The exposure preparation interval is comprised of a radiation source preparation time and a point-in-time when the grid assembly oscillation commences oscillating the grid assembly.

Abstract: In imaging an internal region of the human body, using optical or NMR techniques, a high resolution image is produced by imaging a layer of material formed on the region of interest which conforms to the surface of the region. The material is preferably a lipid, introduced into the body and positioned adjacent the region of interest using a probe.