Abstract: A method and apparatus are disclosed for non-invasively determining the wear of a liner separating a rotatable bearing from a generally spherical housing. The method includes digitizing a first radiographic image of the bearing and housing and processing elements making up the image to define and locate the centers of the bearing and housing within the image. The process is also undertaken for a second radiograph image of the bearing and housing taken earlier than the first radiograph. The movement of the center of the bearing relative to the center of the housing during the time period between the making the first radiographic image and the second radiographic image being related to the wear of the liner.

Abstract: Power is transferred from a stationary power supply to a rotational gantry in a computer tomography (CT) system through a rotary transformer arranged in a ring configuration with an inner diameter that is sufficiently large to receive a patient. The rotary transformer has a toroidal rotor core and a toroidal stator core arranged either concentrically with an air gap extending radially therebetween or side-by-side with an air gap extending axially therebetween. A resonant inverter provides ac power to the rotary transformer which, in turn, drives a high-voltage tank circuit coupled to a x-ray tube, the tank circuit and x-ray tube being mounted on a rotational gantry. Advantageously, this is a contactless power transfer system which eliminates conventional brush and slip ring arrangements and moreover avoids the need for mounting the inverter to rotate with the CT gantry.

Abstract: A gamma ray spectral tool is provided that can be used in slick line systems. The tool includes a battery, a controller, and a memory. In operation, the tool compresses data from the spectral detector for storage in the memory, allowing for long runs without the memory overflowing. Further, a controller latches the self-adjusting stabilization feature of the spectral detector when gamma ray intensity exceeds a predetermined threshold, preventing erroneous "stabilization" by the stabilization feature of the spectral detector.

Abstract: The present invention, in one form, is a method for performing image reconstruction from projection data acquired in a multislice helical scan. More specifically, a helical weighting factors is generated and then a modified weighting factor Wm(.beta.,.gamma.), which is a shifted and weighted average version of the helical weighting factor, is generated. The modified weighting factor is then applied to projection data.

Abstract: A method and apparatus for measuring the concentration of an analyte present in a biological fluid is disclosed. The method includes the steps of applying NIR radiation to calibration samples to produce calibration data, analyzing the calibration data to identify and remove outliers, constructing a calibration model, collecting and analyzing unknown samples to identify and remove outliers, and predicting analyte concentration of non-outliers from the calibration model. Analysis of the calibration data includes data pretreatment, data decomposition to remove redundant data, and identification and removal of outliers using generalized distances. The calibration model may utilize principal component regression, partial least squares, multiple linear regression, or artificial neural networks, and reduction using principal component analysis or partial least squares scores.

Abstract: A method of determining direct x-ray exposure regions in digital medical imaging comprising the steps of: providing a digital medical image including a matrix of lines and columns of pixels; evaluating significant transitions in line and column profiles to determine appropriate line and column thresholds; evaluating all pixels which exceed the line/column threshold for structure by computing the variation within a moving window using a range statistic; accumulating within a histogram pixels which exceed a threshold for that particular line or column and which contain variation indicative of direct x-ray exposure; and analyzing the background histogram to determine the beginning intensity or code value (left point) of the background region.

Abstract: The present invention provides an X-ray tomographic imaging apparatus, wherein image degrading components caused by a CCD sensor (3c) or the like are reduced so as to obtain high-quality X-ray images. After tomographic imaging, dark current noise is eliminated by subtracting dark current correction data from a specific line of data among image data stored in an image memory. Next, sensitivity correction coefficients are prepared on the basis of data obtained when an X-ray beam having nearly uniform intensity distribution enters an X-ray imaging device 3. The image data obtained after dark current correction is then multiplied by the sensitivity correction coefficients. As a result, noise due to sensitivity variations or the like can be eliminated.

Abstract: The invention relates to a medical imaging device using X or gamma ionizing radiation. It comprises a source (S) of radiation in a divergent beam, and a longitudinal slit (F) delivering a sheet-form beam in a plane containing the slit (F). A detection module (1) is provided, which comprises a drift chamber (12) and a multiwire chamber which are filled with a gas. The chambers comprise, in a direction orthogonal to the plane containing the slit (F), the drift space (12) for the electrons, comprising a cathode electrode (11), a converter (121), a proportional multiplier anode (13) for generating multiplied electrons and corresponding ions, and a second cathode electrode (14), placed in the vicinity of the multiplier anode (13). The multiplier anode (13) and the second cathode electrode (14) consist of conductor elements extending in two parallel planes, along substantially orthogonal directions, in order to permit two-dimensional localization of the electrons in this plane.

Abstract: An optical system for x-rays combines at least two spherical or near spherical mirrors for each dimension in grazing incidence orientation to provide the functions of a lens in the x-ray region. To focus x-ray radiation in both the X and the Y dimensions, one of the mirrors focusses the X dimension, a second mirror focusses the Y direction, a third mirror corrects the X dimension by removing comatic aberration and a fourth mirror corrects the Y dimension. Spherical aberration may also be removed for an even better focus. The order of the mirrors is unimportant.

Abstract: A method for processing a radiographic image to obtain a processed image signal Sproc based on an original image signal Sorg. The method including the steps of: obtaining the original image signal Sorg representing the radiographic image based on radiographic image information transmitted through an object; obtaining an unsharp mask signal Sus corresponding to the original image signal Sorg; and conducting an operation presented by the formula: Sproc=A(Sorg)+B(Sus). In the formula, A(Sorg) is the function which does not include the unsharp mask signal Sus, B(Sus) is the function which does not include the original image signal Sorg.

Abstract: An anode assembly for generating x-rays has a mounting block with a channel therethrough, with a diamond wafer mounted sealingly across an opening in the block so as to have an inner surface in contact with the coolant flowing in the channel. Alternatively, a thicker diamond member is mounted in the block with thermal conduction through the metal block. A metal anode film bonded to the outer surface of the diamond is receptive of a focused electron beam to generate x-rays. The diamond provides cooling in compensation for the film being heated by the electron beam. The assembly is useful in a scanning x-ray monochromator instrument for chemical analysis of a specimen surface.

Abstract: The invention relates to an arrangement for measuring the pulse transfer spectrum of X-ray quanta using two polychromatic X-ray sources and a detector arrangement which measures the scattered X-ray quanta in an energy-resolved fashion. A secondary diaphragm device, arranged between the examination zone in which the object whose pulse transfer spectrum is to be determined is situated and the detector device, ensures that each detector element of the detector device can be struck by scattered radiation only at a comparatively accurately determined scatter angle. The arrangement in accordance with the invention enables very fast inspection of an object.

Abstract: An apparatus and method for generating a data set representation of an object or tissue are described. Two image representation data sets for the object or tissue are generated by a CT or MRI scan or other known imaging process. The second data set is preferably generated with enhanced contrast between background tissue and the target tissue of interest, e.g., blood vessels, such as by the injection of a vascular contrast enhancing agent. The first data set is viewed as the union of plural data value neighborhoods, with each neighborhood preferably surrounding a central data value. Each data value of the second data set is compared to a neighborhood in the first data set. If a data value in the second data set is incompatible with the neighborhood, then it is concluded that the data value in the second data set is representative of contrast-enhanced target tissue and is therefore used to generate the final image data set of the target tissue.

Abstract: A method for optimization of radiation therapy planning based on a new Dynamically Penalized Likelihood (DLP) algorithm. The target function of the DLP algorithm contains likelihood terms and penalty terms connected to the likelihood terms by a number of dynamically updated penalty coefficients. The method results in a highly uniform dose to the tumor or radiosurgery volume, at the expense of some non-uniformity in the dose delivered to defined sensitive tissues.

Abstract: Improvements for a positioner for a child being X-rayed are disclosed. The improvements include an improved latch for securing the carriage that supports the X-ray film cassette in a positioner for a child being X-rayed at a position after the carriage is adjusted upwards or downwards; and, the addition of resilient pads for increasing the friction between glide strips and foot members of a positioner for a child being X-rayed so that the foot members will be more effectively secured to the glide strips. The improvements also include an improved latching mechanism used in securing the film holder of the positioner for a child being X-rayed in a position as it is moved towards or away from the upstanding members that secure the child. The buttons that are used to secure the foot members to the glide strip have also been improved by providing them with a tapered bottom surface. The taper compensates for variable thickness in the foot member.

Abstract: The present invention, in one form, is a method for enhancing image sharpness in images generated from CT scan data by using enhancement masks. The enhancement masks are generated, in one embodiment, by generating difference image data from the original age data and low pass filtered image data. The original image data CT numbers are assigned to image regions, e.g., bone, air, and soft tissue, and based on such CT number classifications, certain data in the difference image is fully or partially suppressed. Subsequent to suppressing some difference image data, the difference image data set, which is sometimes referred to as an enhancement mask, is then combined With the original image data to increase image sharpness.

Abstract: In an arrangement for computed tomography imaging, line integral data is converted into a set of Radon data, for use in constructing an image of an object, by computing the derivatives for respective data points in the Radon data set. To improve efficiency in derivative computation, the Radon space is partitioned by a set of concentric spherical shells, so that each of the Radon data points lies on one of the shells. An equal number of spherical shells corresponds to each processor in an array of processors, and each processor is operated to compute respective Radon derivatives only for Radon data points lying on its corresponding shells.

Abstract: A method of generating an image representing fat distributions, comprising the steps of scanning two different levels of tube voltage using a phantom containing a sample rod of a fat standard material and a plurality of sample rods with different densities of a bone mineral equivalent material, to generate two cross sectional image data; detecting the CT number of each pixel in an entire region or an objective region of the cross sectional image data as the CT number of a tissue including fat (.alpha.wf); detecting the CT number of the bone mineral equivalent material to calculate a linear regression between the CT number and the density of the bone mineral equivalent material and to define the CT number of a tissue excluding fat (.alpha.nf); detecting the CT number of the fat standard material (.alpha.ff), while detecting the CT number of a soft tissue standard material (.alpha.st), wherein individual CT numbers are applied to the equation.alpha.wf=.alpha.nf+.beta..multidot.(.alpha.ff-.alpha.st)with .beta.

Abstract: An apparatus and method for rapid real time imaging with wavefield energy by inverse scattering using a C.P.U programmed to process data derived from wavefield energy that has been transmitted and scattered by an object so as to reconstruct a wavefield image of the object. Electronic signals are propagated and are transduced into wavefield energy waves which in turn are propagated toward the object. Detector means detect the wavefield energy waves scattered by the object. The detected wavefield energy waves are then electronically processed and input into a high-speed digital computer which may comprise a C.P.U. and/or a C.P.U in combination with an array or parallel processor.

Abstract: A method and apparatus for reconstructing a three dimensional image of an object from a plurality of two dimensional radiographic images includes the steps of performing radiography of the object from a point source to produce a two dimensional image on a film, backprojecting the two dimensional image through a reconstruction volume to the point source to produce a backprojected image, repeating these steps for a plurality of viewing angles and determining the intersection of the backprojected images and the reconstruction volume. This intersection defines a three dimensional, reconstructed image of the object for each view. Upon superimposition of these three dimensional reconstructed images, the voxels that all the images have in common define a final reconstructed image of the object. Additionally, the present invention includes a stereotactic localizer frame that has eight sides for providing at least four views of the object.