155 results about "X ray attenuation" patented technology

A bowtie filter is constructed to have a fluidic envelope filled with attenuating fluid and a displacement insert that can present various x-ray attenuation profiles during a scan. The insert is designed to displace the attenuating fluid to achieve a denied attenuating or filtering profile. The insert can be rotated, twisted, moved, and otherwise contorted within the fluidic envelope as needed during the course of a scan. As the angle, position and shape of the zombie is changed, the x-ray profile of the filter changes. The insert may have a default shape when at rest, but can have its shape changed when external forces are placed thereon. As x-ray filtering needs change during the course of the scan, the insert can be compressed, stretched, and / or contorted to achieve additional filtering profiles.

A system and method of diagnostic imaging is provided that includes determining a position of a subject in a scanning bay and tailoring x-ray attenuation such that the specific position of the subject is taken into consideration. The present invention automatically selects a proper attenuation filter configuration, corrects patient centering, and corrects noise prediction errors, thereby increasing dose efficiency and tube output.

The invention relates to a medical X-ray device 5 arrangement for producing three-dimensional information of an object 4 in a medical X-ray imaging medical X-ray device arrangement comprising an X-ray source 2 for X-radiating the object from different directions and a detector 6 for detecting the X-radiation to form projection data of the object 4. The medical X-ray device 5 arrangement comprises:means 15 for modelling the object 4 mathematically independently of X-ray imagingand means 15 for utilizing said projection data and said mathematical modelling of the object in Bayesian inversion based on Bayes' formulap⁢(⁢x⁢m)=ppr⁡(x)⁢p(m⁢x)p⁡(m)to produce three-dimensional information of the object, the prior distribution ppr(x) representing mathematical modelling of the object, the object image vector x, which comprise values of the X-ray attenuation coefficient inside the object, m representing projection data, the likelihood distribution p(m|x) representing the X-radiation attenuation model between the object image vector x and projection data m, p(m) being a normalization constant and the posteriori distribution p(x|m) representing the three-dimensional information of the object 4.

Method and device for digital x-ray tomosynthesis. Tomographic and / or three-dimensional images of an object are obtained with an x-ray source and a digital x-ray image sensor. The source, object and sensor are positioned relative to each other and attenuation data is obtained for a large number of rays of x-radiation through the object. A special algorithm is provided to convert the data into images. To calculate the images the algorithm uses iterative processes with a least squares type technique but with generalized (as opposed to specific) functions. The algorithm solves for the functions which are the images. Preferred embodiments include a system having an x-ray point source with a cone of diverging x-rays, a two-dimensional digital x-ray image sensor, two linear translation stages to independently move both the x-ray source and the digital x-ray image sensor, two rotation mechanisms to rotate the two linear translation stages, a microprocessor to control the data acquisition, and a computer programmed with a special algorithm to calculate the tomographic images. A plurality of sets of digital data (representing x-ray algorithm images of an object) are acquired by the digital x-ray image sensor, with the x-ray source and the digital x-ray image sensor located at different positions and angles relative to the object. The digital data representing the x-ray attenuation images is stored in the computer. Special mathematical algorithms then compute multiple images of the object using the acquired digital data. These images could include multiple tomographic images, a three-dimensional image, or a multiple three-dimensional images.

A method of determining a parameter of interest of reservoir rock formation is described using the steps of measuring an x-ray attenuation or absorption distribution of a sample of said rock formation, identifying the mineral phase part of said distribution, and subdividing the mineral phase part of said distribution to derive classification or rock type information of said sample.

A bowtie filter is constructed to have a fluidic envelope filled with attenuating fluid and a displacement insert that can present various x-ray attenuation profiles during a scan. The insert is designed to displace the attenuating fluid to achieve a denied attenuating or filtering profile. The insert can be rotated, twisted, moved, and otherwise contorted within the fluidic envelope as needed during the course of a scan. As the angle, position and shape of the zombie is changed, the x-ray profile of the filter changes. The insert may have a default shape when at rest, but can have its shape changed when external forces are placed thereon. As x-ray filtering needs change during the course of the scan, the insert can be compressed, stretched, and / or contorted to achieve additional filtering profiles.

An image reconstruction method for cone beam x-ray attenuation data acquired over a super-short-scan, short-scan or full-scan includes backproejcting over three adjacent segments of the arc traversed by the x-ray source. Each backprojection consists of a weighted combination of 1D Hilbert filtering of the modified cone-beam data along both horizontal and non-horizontal directions.

A system and method are provided for model-based coronary artery calcium (CAC) scoring. A model image of a heart region is aligned with an image of a patient's heart region in order to more easily identify the coronary arteries and other relevant anatomical features in the image. Once the images are aligned, relevant calcium plaques are identified by their presence within a coronary artery, and the relevant plaques are then labeled by the specific coronary artery in which they are located. The coronary arteries with the labeled plaques are scored individually based on their size and X-ray attenuation, and an overall score based on all of the relevant plaques is then computed, which is related to the patient's risk for coronary artery disease.

A method uses a computer and software to measure bone density and structure of the proximal femur of the hip from a volumetric set of images containing pixels representing x-ray attenuation of the subject which are acquired with three-dimensional X-ray imaging devices. The method automatically locates anatomical markers of the hip without operator interaction, automatically positions regions of interest (ROIs) for measurement, automatically determines bone density measures of the ROIs, and automatically reports the results for individual subjects. Bone density measurements of ROIs include the integral bone of the total hip and neck as well as trabecular bone. The method automatically identifies a three-dimensional region-of-interest (ROI) volume which includes the hip, determines a three-dimensional coordinate system referenced to the anatomy of the subject, analyzes the ROI volume to identify voxels in the volume which satisfy defined criteria, and determines a measure of bone structure.

An X-ray CT apparatus acquires a scanogram of an object to be examined, generates an ellipse model having an X-ray attenuation coefficient equivalent to that of water and approximated to a tomographic image of the obtained imaged portion from the feature quantity of the projection value profile, determines whether or not the generated elliptic model is adequate as a model of the imaged portion from another feature quantity with respect to the projection value profile, generates a corrected elliptic model according to yet another feature quantity with respect to the projection value profile if the elliptic model is determined to be inadequate, and controls the modulation of the tube current in an X-ray source so that a predetermined target SD value is maintained in any scanning position when a tomographic image is reconstructed according to X-rays transmitted through the object by using the elliptic model or the corrected elliptic model.

A method of determining a parameter of interest of reservoir rock formation is described using the steps of measuring an x-ray attenuation or absorption distribution of a sample of said rock formation, identifying the mineral phase part of said distribution, and subdividing the mineral phase part of said distribution to derive classification or rock type information of said sample.

System and method for XRD-based false alarm resolution in computed tomography (“CT”) threat detection systems. Following a scan of an object with a megavoltage CT-based threat detection system, a suspicious area in the object is identified. The three dimensional position of the suspicious area is used to determine a ray path for the XRD-based threat detection system that provides minimal X-ray attenuation. The object is then positioned for XRD scanning of the suspicious area along this determined ray path. The XRD-based threat detection system is configured to detect high density metals (“HDMs) as well as shielded Special Nuclear Materials (“SNMs”) based on cubic or non-cubic diffraction profiles.

A novel process is for making ceramic based radiopac materials useful for X-ray radiation attenuation. The process is lead as well as rare earth free and thus obviates (i) the use of conventionally used lead metal and its compounds—which are toxic in nature and are heavy weight as the density of lead is 11.34 gm / cm-2. Further the low melting points of lead (325° C.) prohibits its use in high temperature shielding structures and (ii) the use of Rare earth is restricted because they are very costly and scarcely available. The novel process of the present invention utilizes different varieties of waste as raw materials such as fly ash (from thermal power plants), Red mud (from aluminum production), Rice husk silica (an agro waste) and pyrophyllite (an underutilized clay mineral). These waste materials contain various necessary constituents required for making radiopac materials namely silicon, titanium, iron and aluminum. The presence of different mineralizers in the raw materials used and use of phosphatic binders significantly helps in obtaining the radiopac materials, at relatively low temperature of 920° C. itself and thus leads to saving of considerable heat energy. Further as the waste are generated in powder form, the use of these waste also helps in saving on the account of grinding energy. The radiopac materials obtained by the novel process of present invention are capable of withstanding ambient to high temperature and thus finds wide applications in making aprons, gloves and ceramic tiles, bricks for attenuation of X-ray radiations. The radiopac materials are useful as materials for construction of partition wall of X-ray room in hospitals, research institutes and industries. Apart from this radiopac materials an also be used and in making high temperature X-ray attenuation structures.

An X-ray optical alignment system for X-ray imaging devices includes a visible-light point source and a multi-axis positioner therefor, fixedly mounted with respect to the X-ray focal spot. A mirror or beamsplitter is fixedly mounted with respect to the X-ray focal spot and disposed in the beam path of the X-ray source. The beamsplitter reflects light emitted from the light source and transmits X-rays emitted from the X-ray source. A first X-ray attenuating grid is fixedly but removably mountable with respect to the X-ray source, having a first X-ray attenuation pattern; and a second X-ray attenuating grid is adjustably mountable with respect to the first grid having a second X-ray attenuating pattern corresponding to the first X-ray attenuating pattern. When the grids are aligned, their attenuating patterns are also aligned and allow X-rays from the X-ray source and light reflected from the beamsplitter to pass therethrough.

An X-ray CT apparatus includes a unit which extracts a high-contrast region of comparatively high X-ray attenuation coefficient from an image, units which generate an unsharp image concerning the high-contrast region, on the basis of the position of the extracted high-contrast region and a point spread function peculiar to the apparatus, and a unit which subtracts the unsharp image from the original image in order to generate a low-contrast image concerning a low-contrast region of comparatively low X-ray attenuation coefficient.

The invention relates to a method and a device for automatically differentiating bones or other calcium-containing materials and contrast agent in soft tissue of an object area. In at least one embodiment of the method, two image data records of two computed tomography pictures of the object are provided that have been recorded in the context of a different spectral distribution of the X-radiation. For voxels of at least one interesting slice, there is calculated from the two image data records a ratio r that is yielded from measured or averaged X-ray attenuation values of the respective voxel or its environment in the context of the different spectral distributions of the X-radiation and prescribed X-ray attenuation values of soft tissue in the context of the different spectral distributions of the X-radiation according to a prescribed calculation rule. Upon overshooting of a threshold value for the ratio r the respective voxel is assigned either contrast agent or calcium-containing material as a function of the magnitude of r. The proposed method and / or the associated device enable a reliable automatic differentiation of bones or other calcium-containing materials and contrast agent in computed tomography pictures.

A technique is provided for non-uniform weighting in back-projection calculations in tomosythesis. The non-uniform weighting may include weighting based on a count map of the number of times pixels of individual slices are traversed by radiation in different projections. Weighting may also include non-uniform functions for contributions of features at different slice level to the sensed X-ray attenuation system response inconsistencies are accounted for by further weighting based upon projection maps which may be created in separate system calibration or configuration routines.