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.