Abstract: A method and system for the automated detection of lesions in computed tomographic images, including generating image data from at least one selected portion of an object, for example, from CT images of the thorax. The image data are then analyzed in order to produce the boundary of the thorax. The image data within the thoracic boundary is then further analyzed to produce boundaries of the lung regions using predetermined criteria. Features within the lung regions are then extracted using multi-gray-level thresholding and correlation between resulting multi-level threshold images and between at least adjacent sections. Classification of the features as abnormal lesions or normal anatomic features is then performed using geometric features yielding a likelihood of being an abnormal lesion along with its location in either the 2-D image section or in the 3-D space of the object.

Abstract: A scanning and data acquisition method and apparatus for three dimensional (3D) computerized tomography (CT) imaging of a region-of-interest (ROI) in an object, wherein image reconstruction processing is applied to a plurality of sets of cone beam projection data, each set being acquired on a detector at a corresponding plurality of scan path source positions. A first image reconstruction processing step comprises applying a mask to each set of the projection data to form masked data sets. The mask for each data set is formed by cone beam projections onto the plane of the detector of portions of the source scan path that are above and below the source position that acquired the data set being masked.

Abstract: In an x-ray computed tomography imaging system, it is often useful to have access to the unreconstructed CT projection data, called sinogram data. Scout image data can be converted to a sinogram using a series of computer implemented algorithms, since the original sinogram data may be unavailable or in a proprietary format. Using this conversion, multiple scout images may be substituted for unavailable sinogram data.

Abstract: A medical system, such as an X-ray diagnostic device, having adjustable components, including a patient table, and having a monitoring device for determining the relative positions of the components and preventing collisions between them. Signals indicating the positions, the directions of motion and the speeds of movement of the components are fed directly from the drives and sensors of the components to the monitoring device. Calculations for controlling the components are carried out by a neural network, which has been appropriately trained in a learning phase.

Abstract: In a method for producing a tomosynthesis exposure a reference object is used which is formed by a region of the examination subject. It is thus possible to determine the distance of the beam transmitter to the beam receiver and to the examination subject, the irradiation angle, and the direction of irradiation, on the basis of the signals that can be derived from the beam receiver during the transillumination of the reference object, without the reference object causing any disturbance in the region of the subject of examination.

Abstract: A scanning and data acquisition technique for three dimensional (3D) computerized tomographic (CT) imaging of an object, wherein scanning at a plurality of positions along a source scanning trajectory causes an area detector to acquire cone beam projection data corresponding to a shadow of said object at each of scanning positions and Radon derivative data is calculated by processing line integral values from cone beam projection data. In order to improve the calculation efficiency of the Radon derivative calculation, calculation of the Radon derivative data uses a determination of the left and right boundaries of the shadow for each of the scanning positions, and calculates the Radon derivative data only using projection data from within the determined boundaries.

Abstract: A radiographic apparatus which can improve at high speed the picture quality of an X-ray fluoroscopic image or an X-ray radiographic image is disclosed.

Abstract: In a spiral scan computed tomography apparatus, and a method for reconstructing an image from spiral scan data, a measurement system composed of an x-ray source and a radiation receiver is rotated in a plane around an examination subject on a support table, while producing a feed of the support table relative to the rotation plane of the measurement system. Radiation emitted by the x-ray source, attenuated by the patient, strikes the radiation receiver, thereby producing measured signals representing spiral attenuation values. A computer is supplied with the spiral attenuation values and generates weighted spiral attenuation values therefrom using a weighting generator, by which data from a number of planar image superimpositions are employed. The number of superimpositions, the spacing of the superimpositions, and the strength of a k.sup.th superimposition contribution can be independently selected.

Abstract: The invention includes both systems and methods for tomosynthesis x-ray imaging. An x-ray source is moved at various positions in an arc around an object, e.g., a breast, to illuminate a stationary digital detector (or its equivalent) placed at an image plane behind the object. A digital image data processor collects data from the detector and a motion controller moves the source around the object. As the source moves along the arc, the detector generates, for a succession of points along the arc, a corresponding succession of image data sets, each set being representative of the intensity of x-rays incident on the detector for the then current position of the source. The image data processor is responsive to the image data sets to generate an output image signal representative of the x-ray absorption of points within the object region.

Abstract: In medical imaging in which a plurality of images of an object under examination are formed, image distortions are corrected using a phantom body which is present in the examination zone of the imaging device when the images of the object are acquired. It is known that image distortions in computer tomography apparatus are caused, for example, by calibration errors, by deviations from the adjusted table displacement speed, or by bending of the table under the weight of the patient. These image distortions are detected in the image of the phantom body in an acquired image and a correction rule is derived for the correction of image distortions in the entire acquired image. The phantom body is in the form of a frame of three elements of X or N shape, two of which extend parallel to one another and perpendicular to the third.

Abstract: In a method for reducing a radiation dose in an x-ray CT (computed tomography) system, a maximum x-ray attenuation per projection is computed for every projection or for every n.sup.th projection and the measured angular attenuation profile for a last half rotation of the x-ray beam around a subject is stored, an extrapolation method is conducted for computing an extrapolated attenuation profile for a next half rotation based on the measured angular attenuation profile for the last half rotation, and a process is conducted for setting a dose level for the x-ray beam for a next projection, based on the extrapolated attenuation profile. The x-ray beam can be modulated, with characteristics of the beam modulation being set or controlled dependent on the extrapolated attenuation profile.

Abstract: A system for spectroscopic imaging of bodily tissue in which a scintillation screen and a charged coupled device (CCD) are used to accurately image selected tissue. An x-ray source generates x-rays which pass through a region of a subject's body, forming an x-ray image which reaches the scintillation screen. The scintillation screen reradiates a spatial intensity pattern corresponding to the image, the pattern being detected by a CCD sensor. The image is digitized by the sensor and processed by a controller before being stored as an electronic image. Each image is directed onto an associated respective CCD or amorphous silicon detector to generate individual electronic representations of the separate images.

Abstract: The present invention, in one form, is a system for generating a high resolution image of an object from projection data acquired during a computed tomography scan. The system includes a gantry having an x-ray source which rotates around the object. The x-ray source emits an x-ray beam which is collimated with a collimator having a collimator aperture to define an x-ray beam width, or slice thickness. The projection data is reconstructed to generate image data for adjacent image slices. A deconvolution algorithm is applied to the image data to generate a deconvolved image having a finer, i.e., smaller, resolution than the collimator aperture.

Abstract: A method and apparatus for reconstructing an image of an object using a three dimensional (3D) computerized tomographic (CT) imager having a cone beam radiation source and detector arrangement for acquiring measurement data. Before the acquisition of measurement data during an imaging operation of the apparatus, image reconstruction processing information dependant on the geometric parameters of the imager and required for processing of the acquired measurement data for developing contributions to the final reconstruction of the image, is pre-calculated and stored. During an imaging operation of the apparatus, the acquired measurement data is processed using the pre-calculated image reconstruction processing information for reconstructing the image.

Abstract: An autosegmentation/autocontouring method that may be used for quickly and accurately contouring the regions and boundaries around regions for the development of cross-sections that may be linearly disposed for the three-dimensional reconstruction of an image is described and claimed. The autosegmentation/autocontouring method includes at least four steps. The first step is to digitize a CT, MRI, or other suitable image and display it on a display screen. The two-dimensional image on the display screen will include gray-scale representations of the internal organs and tissue masses of the anatomical site through which the cross-section was made. The second step is to select the interior of a ROI and draw a polygon within the boundaries of the cross-sectional view of this ROI. This polygon could also be drawn in the interior of a cancerous mass or other diseased tissue.

Abstract: The composition of a multiphase fluid with varying salinity is measured by radiating a photon beam through the fluid and measuring the level of radiation absorption by the fluid at at least radiation energy levels and feeding the thus obtained radiation absorption data to a data processor which generates data concerning the fluid composition, including its salt content, if any, on the basis of a phase fraction calculation scheme in which radiation absorption by salt is taken into account.

Abstract: An X-ray imaging method, and device for carrying out the method, utilizes a first imaging device to form and digitally store a series of two-dimensional X-ray images in which an object to be examined is projected onto an X-ray image pick-up device from different perspectives, and a second imaging device to form a three-dimensional image of the same object. Quasi three-dimensional reproduction of anatomic structures is achieved by extracting a relevant structure of the object to be examined from the three-dimensional image, calculating synthetic, two-dimensional projection images of the extracted structure, the structure being projected with the same geometrical parameters as used for the relevant structure during the formation of the individual X-ray images, forming superposition images by superposing the synthetic projection images and the X-ray images formed under the same geometrical conditions, and displaying the series of superposition images.

Abstract: A display signal of high contrast is generated by processing an image signal that is acquired from a camera such as an infra-red or X-ray camera.

Abstract: An x-ray or neutron optic configuration includes a plurality of single crystal portions formed with respective spaced x-ray or neutron reflection faces formed at predetermined asymmetry angles to a Bragg diffraction plane in the respective crystal portion. The crystal portions are interconnected to maintain a first and second of these faces spaced apart for receipt of a sample between them and to allow small adjustments of the relative angle of the faces about the normal to the plane of diffraction while maintaining the normals to the Bragg planes for the first and second faces substantially in the plane of diffraction. A first face is arranged to be a monochromator and collimator with respect to x-rays or neutrons of appropriate wavelength incident reflected through the sample for receipt by the second face, which thereby serves as analyzer face.

Abstract: A locally-adaptive method for obtaining sub-pixel registration of mask and opacified digital X-ray images includes the steps of match point generation, locally-adaptive image-to-image warp generation, and log subtraction, for generating a DSA image. Specifically, in match point generation, a set of two-dimensional points in the mask image and their corresponding points in the opacified image are derived. After match point generation, locally-adaptive image-to-image warp generation is performed using the image-to-image match points; that is, a transformation function is generated that maps the matched points in the mask image to their corresponding points in the opacified image. The generated transformation is then applied to the mask image data and the logarithm of the pixel value in the transformed (i.e., warped) mask image is subtracted from the logarithm of the corresponding pixel value in the opacified image.