Abstract: A method and apparatus is disclosed for inspecting a wall to evaluate the remaining thickness of the wall as well as the extent to which the wall has been infiltrated by another material. The disclosure discusses directing photons of radiation and/or neutrons into the wall and measuring and analyzing the radiation emitted from the wall as a result of Compton scattering, pair production, photoelectric absorption and/or neutron absorption. The invention is particularly well suited for inspecting a carbon hearth-wall liner of an iron-smelting blast furnace.

Abstract: A liquid metal/solid metal interface detecting device comprises in general a radiation source for generating gamma radiation, which is directed to pass through a strand extruded from a continuous casting mold. A detector detects the gamma radiation passing through the partially solidified strand to determine a spatial profile for a liquid metal/solid metal interface by relying on the different gamma radiation attenuation characteristics of the solid metal and the liquid metal. Preferably, the gamma radiation is at energies of greater than one million electron volts. In some embodiments, a movable support carries the radiation source and the detector and moves the radiation source and detector along and around the ingot enabling generation of a three-dimensional profile of the liquid metal/solid metal interface by utilizing tomographic imaging techniques.

Abstract: A liquid metal/solid metal interface detecting device comprises in general a radiation source for generating gamma radiation, which is directed to pass through a strand extruded from a continuous casting mold. A detector detects the gamma radiation passing through the partially solidified strand to determine a spatial profile for a liquid metal/solid metal interface by relying on the different gamma radiation attenuation characteristics of the solid metal and the liquid metal. Preferably, the gamma radiation is at energies of greater than one million electron volts. In some embodiments, a movable support carries the radiation source and the detector and moves the radiation source and detector along and around the ingot enabling generation of a three-dimensional profile of the liquid metal/solid metal interface by utilizing tomographic imaging techniques.

Abstract: Methods and apparatus for precise and consistent selection of bone mineral content (BMC) measurement regions of selected bones, and accurate calculation of BMC from a displayed radiological image of the bones, calculate the position of the styloid tip of each bone, define a measurement region having selected positional correspondence to the position of the styloid tip, and sum pixel intensity values in the measurement region to yield a pixel intensity sum representative of bone mineral content. Bone density values are obtained by dividing the pixel intensity sum by a value representative of the areas of the measurement region, to yield a value representative of bone density. The position of the styloid tip is calculated by detecting selected transverse image edges, searching along the selected transverse image edges to determine a set of pixels which define extremities of the styloid tip, and defining a line substantially tangent to the styloid tip.

Abstract: A data acquisition system is disclosed for use in radiographic imaging. The acquisition system includes at least two memory banks for storing radiographic data from a radiation detector, acquisition circuitry for sensing radiographic data when transmitted by the detector and for writing such data into one of the memory banks, and a controller for selecting a memory bank for storage of the data, and for switching from one memory bank to another, as well as for reading data from one or the other memory banks when such memory bank is not actively acquiring data.

Abstract: A readout system is disclosed for use in conjunction with a radiation detector to obtain radiographic images. The readout system includes an event gating mechanism for receiving signals which are simultaneously generated at a plurality of locations within a radiation detector in response to a radiation event and an estimating mechanism for identifying the locus of the radiation event from the signals. In one illustrated embodiment the event gating mechanism further includes circuitry for receiving signals from a first and second set of lines defining a 2-dimensional coordinate grid within an area radiation detector.

Abstract: Devices and apparatus for limb positioning and instrument calibration are disclosed for use in radiographic imaging systems. In one aspect of the invention, a limb positioning device is disclosed, including a support surface for placement of a limb (e.g., typically a wrist) thereon, a pair of side blocks, at least one of which is moveable to accommodate placement of the limb therebetween, a biasing mechanism for urging the blocks together, and a clamping mechanism for immobilizing the limb between the side blocks and upon the support surface.

Abstract: Radiation detection methods and apparatus measure ionizing radiation propagating from a radiation source, utilizing a chamber having an electrically conductive sheet, an electrode assembly spaced apart from the conductive sheet and segmented into a plurality of electrically discrete electrode segments, and an ionizable medium disposed between the electrode assembly and conductive sheet, for absorbing the ionizing radiation and generating charged particles in proportion to the radiation energy absorbed. An electrical potential can be provided between the electrode assembly and conductive sheet, so that respective electrode segments collect the charged particles. Elements are provided for comparing the number of charged particles collected on respective electrode segments, to provide a measure of the energy distribution of the ionizing radiation, and for compensating for changes in capacitance or electrical potential between the electrode segments and the electrically conductive sheet elements.

Abstract: A system for analyzing biological structures by photon absorptiometry is disclosed, including a radiation source emitting photons and at least one source filter which operates to reduce the emission of high energy photons, thereby creating a sharp drop-off at the high end of the detected energy spectrum. The filter radiation is received by a detector which determines the spatial intensity of the radiation over the image area and preferably has a characteristics response which is relatively insensitive to low energy photons, such that the source filter and detector cooperate to measure the intensity of photons within a narrowed band of energy levels.

Abstract: A method and apparatus for determining the distribution of a position-emitting radioisotope into an object, the apparatus consisting of a wire mesh radiation converter, an ionizable gas for propagating ionization events caused by electrodes released by the converter, a drift field, a spatial position detector and signal processing circuitry for correlating near-simultaneous ionization events and determining their time differences, whereby the position sources of back-to-back collinear radiation can be located and a distribution image constructed.

Abstract: Radiation imaging apparatus especially suited for use in a computerized tomographic (CT) scanner employs an array of discrete X-ray sources, each being a cold cathode diode and an adjacent fixed array of closely packed radiation detectors to produce images of rapidly moving body organs such as the beating heart. A variety of alternative X-ray source embodiments are also disclosed.

Abstract: A radiation imaging system employs a superheated, superconducting colloid detector subjected to an external magnetic field so that the colloid grains are maintained in a metastable superconducting state in the absence of radiation. Intersecting sets of select wires are imbedded in the detector that divide the detector into volumetric resolution elements. Grains in each resolution element that absorb photons emanating from an object "flip" to the normal conducting state. By applying coincident currents to the select wires defining each element, a local magnetic field is produced that opposes the external field so that all the "flipped" grains are reset to the superconducting state. This produces a flux change proportional to the number of photons incident on that element which is sensed and used to develop an x-ray image of the object.

Abstract: A radiation imaging system employs a super-heated, super-conducting colloid detector subjected to an external magnetic field such that all the colloid grains are maintained in the metastable super-conducting state in the absence of radiation. Imbedded in the detector are intersecting helical sensing coils that divide the detector into volumetric resolution elements. The grains in each element that absorb x-ray or gamma ray photons emanating from an object make a transition to the normal conducting state thereby producing flux changes in the vicinities of the grains which induce signals in the coils defining the resolution element in which those grains are located. The number of signals from each element are accumulated separately and used to produce an image of the object.