Abstract: An imaging system includes a detector configured to detect X-rays from an X-ray source. The detector includes multiple photodetector elements. The imaging system also includes an anti-scatter grid disposed over the detector, wherein the anti-scatter grid includes multiple radiation absorbing elements. At least a portion of one or more of the radiation absorbing elements of the multiple radiation absorbing elements is disposed on each photodetector element, and a total area of each respective portion of the one or more radiation absorbing elements disposed on each photodetector element is substantially equal.

Abstract: A cassette holder of an imaging stand is provided with first and second catch members for catching and holding an electronic cassette from above and below. The first catch member has a multi connector connected to a multi terminal of the electronic cassette. The multi connector is offset with respect to a center line of an imaging surface of the cassette holder. The multi terminal is offset with respect to a center line of an irradiation surface of the electronic cassette in the same direction by the same amount as those of the multi connector. In a state where said electronic cassette mounted on a tray is loaded into the cassette holder, the center line of the irradiation surface coincides with the center line of the imaging surface.

Abstract: A computer-implemented method for gain calibration is provided. The method includes sorting the calibration data of each pixel location from the offset-corrected X-ray image data into a sequence. The method also includes removing part of the calibration data from one end or both ends of the respective sequence for each pixel location. The method further includes averaging the calibration data remaining within each respective sequence to obtain an average pixel value for each pixel location. The method yet further includes generating a gain map based on the average pixel value for each pixel location.

Abstract: A method for reconstructing an image from emission data includes generating a compressed point-spread function matrix, generating an accumulated attenuation factor; and performing at least one image projection operation on an image matrix of the emission data using the compressed point-spread function matrix and the accumulated attenuation factor. The image projection operation can include rotating an image matrix and an exponential attenuation map to align with a selected viewing angle. An accumulated attenuation image is then generated from the rotated image matrix and rotated exponential attenuation map and a projection image is generated for each voxel by multiplying the accumulated attenuation image and point spread function matrix for each voxel. The rotating and multiplying operations can be performed on a graphics processing unit, which may be found in a commercially available video processing card, which are specifically designed to efficiently perform such operations.

Abstract: An estimation selecting unit is provided to select an estimating method based on a predetermined value. When variations due to a statistical error of each pixel concerned are enlarged by a greater extent than variations of other pixels, and hence a possibility of becoming conspicuous on the image, then the direct ray transmittance at the pixel concerned is considered less than the predetermined value, and estimated direct ray intensity is obtained for the pixel concerned by interpolating calculation of estimated direct ray intensities at pixels surrounding the pixel concerned.

Abstract: An air grid is constructed such that absorbing foil strips, which absorb scattered X-rays, are arranged in a direction parallel to the direction of rows of detecting elements, and that spacing between adjacent shadows among shadows of the absorbing foil strips formed on a flat panel X-ray detector (FPD) as a result of the absorbing foil strips absorbing X-rays is larger than spacing between pixels forming an X-ray image. An image data acquiring unit, a transmittance smoothing unit, a grid data acquiring unit, a shadowless pixel calculating unit, a shadow total quantity calculating unit, a transmittance correcting unit and an X-ray image acquiring unit are provided to remove the shadows with high accuracy by using corrected image data (X-ray transmittances) which constitutes a profile of shadows occurring at an actual time of X-ray imaging of a subject.

Abstract: A radiography device that can be applied to even general-purpose scattered radiation removing means, capable of producing appropriate radiation images that are independently of the status of installation of scattered radiation removing means. A pixel specifying portion specifies particular pixels of the various pixels that comprise an x-ray image. An intensity estimating portion estimates the scattered x-ray intensities (scattered radiation intensities) at the particular pixels specified by the pixel specifying portion and/or the direct x-ray intensities (the direct radiation intensities) of the particular pixels. Consequently, it is possible to estimate appropriately the scattered x-ray intensities and/or direct x-ray intensities at the particular pixels in consideration of the status of installation of a grid (scattered radiation removing means).

Abstract: A system and method for forming an adjusted estimate of scattered radiation in a radiographic projection of a target object, which incorporates scattered radiation from objects adjacent to the target object, such as a patient table. A piercing point equalization method is disclosed, and a refinement of analytical kernel methods which utilizes hybrid kernels is also disclosed.

Abstract: An estimation selecting unit is provided to select an estimating method based on a predetermined value. When variations due to a statistical error of each pixel concerned are enlarged by a greater extent than variations of other pixels, and hence a possibility of becoming conspicuous on the image, then the direct ray transmittance at the pixel concerned is considered less than the predetermined value, and estimated direct ray intensity is obtained for the pixel concerned by interpolating calculation of estimated direct ray intensities at pixels surrounding the pixel concerned.

Abstract: The present invention provides an X-ray attenuation correction method, image generating apparatus, X-ray CT apparatus, and image generating method for correcting for the attenuation of X-ray beam at the boundary where the X-ray absorption rate of a subject is changing. Boundary information comprised of the boundary position where the X-ray absorption rate is changing and the magnitude of change is extracted from the projection information of the subject, then the boundary information is used to multiply the amount of scattered X-ray by the amount corresponding to the magnitude of change at the boundary position, to correct for the attenuation of X-ray at the boundary position. The attenuation of X-ray at the boundary position may be corrected for along with the scattered X-ray correction of the projection information, allowing alleviating artifacts developed in a tomographic image.

Abstract: Cone-beam CT scanners with large detector arrays suffer from increased scatter radiation. This radiation may cause severe image artefacts. An examination apparatus is provided which directly measures the scatter radiation and uses this measurement for a correction of the contaminated image data. The measurement is performed by utilizing a 1-dimensional anti-scatter-grid and an X-ray tube with an electronic focal spot movement. Image data is detected at a first position of a focal spot and scatter data is detected at a second position of the focal spot. The image data is corrected on the basis of the scatter data.

Abstract: For scattered radiation correction in dual X-ray absorptiometry it is proposed to use the additional information supplied by the attenuation images in different energy ranges in a correction image area with homogeneous attenuation coefficients in order to determine the respective scattered radiation fraction. Toward that end, the inverse of the primary radiation function is considered and a search conducted for that scatter-to-primary ratio which leads to consistent mass per unit areas for the attenuation images recorded in different energy ranges.

Abstract: The invention relates to a method, to an X-ray apparatus for performing the method and to a detector arrangement intended for the latter, for producing X-ray images containing a reduced proportion of scattered radiation. The X-ray radiation is detected in this case by a detector arrangement comprising two X-ray detectors, there being provided in the first X-ray detector openings through which the second X-ray detector is able to detect scattered radiation and primary radiation by separate detector elements. The signals given by the second X-ray detector are used to determine the proportion of scattered radiation that is contained in the image produced by the first X-ray detector and to largely free the first image of the proportion of scattered radiation.

Abstract: The present invention relates to a method for scattered radiation correction in X-ray imaging, and to an X-ray imaging system for carrying out the method. In the method, measurement signals t from an X-ray detector (9) are digitized and converted to logarithmic form, with these measurement signals t having been obtained by radiation through an examination object (10) by the X-ray detector (9). Correction values which have been obtained from a series development of a logarithm ln(1?s/t) are subtracted from the measurement signals that have been converted to logarithmic form, with this series development being terminated at the earliest after the first order, where s denotes a previously determined scattered radiation signal from radiation passed through the examination object (10). The method and the associated X-ray imaging system allow scattered radiation to be corrected for with increased accuracy, on the basis of measurement signals that had been converted to logarithmic form.

Abstract: An apparatus for projection radiography is set up for correcting stray radiation. The apparatus comprises an evaluation unit which evaluates the distribution of stray radiation, which is arranged in a tabular manner in a data memory, for correcting stray radiation, said distribution being initially determined with the aid of Monte-Carlo-Simulation which takes into account multiple interactions of the photons with the object which is to be analyzed.

Abstract: The method is analytical, involves a single irradiation of the object at a plurality of incidences in order to obtain a first three-dimensional image of the total radiation received by the detector, but a double irradiation of a set of calibration phantoms, such as planar plates, in order to obtain their images of the total radiation and the scattered radiation. The three-dimensional image serves only to precisely evaluate, for each projection of the radiation through the object, the equivalent length of the material of the phantoms in order to obtain a similar scattered radiation. In a known manner, a ratio of scattered radiation layers is then calculated for the object and the phantoms according to the total radiation that they have received, and the scattered radiation of the object is obtained by the radiation scattered by the phantoms, which have been measured, and the ratio.

Abstract: An image processing method which corrects a 3-dimensional CT data value obtained from a 3-dimensional object is provided. The image processing method comprises: a threshold setting step of setting a threshold value used for generating a correction value from the 3-dimensional CT data value obtained from the 3-dimensional object; an average calculating step of calculating an average value of a 3-dimensional CT data block comprising a 3-dimensional CT data element of a correction target and a plurality of 3-dimensional CT data elements in a neighborhood of the 3-dimensional CT data element of the correction target; and a correction step of correcting the 3-dimensional CT data value by using the threshold value set in the threshold setting step and the average value obtained in the average calculating step.

Abstract: A system for obtaining a resultant image and a method to utilize the same are provided. In particular, first and second images of a subject or a portion of the subject are obtained. The first image includes a first portion of the subject and a second portion of the subject, and each of the first image and the second image are different types of images. A first probability that the first portion has a contrast which is greater than a predetermined contrast and a second probability that the second portion has a contrast which is greater than the predetermined contrast then is determined using the second image. For example, the second probability is greater than the first probability. Moreover, the first and second portions of the first image are reconstructed to generate the resultant image. Specifically, the first portion is reconstructed based on the first probability and the second portion is reconstructed based on the second probability.

Abstract: A device (1) for computer tomography, which is set up for x-ray scatter correction, features an evaluation unit (17) which evaluates values stored as a table in a data memory for x-ray scatter correction, which have been determined in advance with the aid of a Monte Carlo simulation which take account of interactions of the photons with the object (2) to be investigated.

Abstract: A system includes acquisition of a first image of a first radiation field, at least a portion of the first radiation field comprising radiation attenuated by a device, and the first image including a representation of first scatter radiation generated during acquisition of the first image, acquisition of a second image of a second radiation field, at least a portion of the second radiation field comprising radiation attenuated by a volume corresponding to the device, and the second image including a representation of second scatter radiation generated during acquisition of the second image, and modification of the second image based on the first image to compensate for the second scatter radiation.

Abstract: The invention relates to a method for producing X-ray images, by which successive X-ray images are recorded using a first semiconductor detector arranged in a first plane and a second semiconductor detector arranged in a second plane. For the purpose of correcting the X-ray images it is proposed that dark images are recorded intermittently, and these are subtracted from the X-ray images subsequently generated.

Abstract: A method for performing scattered radiation correction. The position of a collimator and the width of a slit are adjusted so that direct radiation will fall on one of a plurality of arrays of detectors. A predetermined phantom is scanned. The scan is performed relative to each of the plurality of arrays of detectors. Based on data detected during each scan, scattered radiation correction data is produced. The produced scattered radiation correction data is used to correct projection data acquired by scanning a subject.

Abstract: A method for obtaining an X-ray image for an X-ray diagnosis apparatus including plurality of imaging systems, including: collecting first scatter data using a first X-ray detector after an X-ray is irradiated from a first X-ray tube in a first imaging system; collecting second scatter data using a second X-ray detector after an X-ray is irradiated from a second X-ray tube in a second imaging system; collecting first image data including a scatter component using X-ray detectors after an X-ray is irradiated from a third X-ray tube in the first imaging system; collecting second image data including a scatter component using X-ray detectors after an X-ray is irradiated from a fourth X-ray tube in the second imaging system; and obtaining X-ray images for the first and second imaging systems by subtracting the first and second scatter data from the first and second image data including a scatter component, respectively.

Abstract: An apparatus and method are provided for determining whether diaphragmatic radiation has been employed to obtain an autoradiograph of an object using a radiographic device having a diaphragmatic radiation function. An autoradiographic signal is entered and a first characteristic value is calculated using an autoradiograph designated by the autoradiographic signal, and then a frequency is calculated for the appearance of a density value for pixels constituting the edge of the autoradiograph that is determined using the first characteristic value and the frequency is employed to determine whether diaphragmatic radiation was used.

Abstract: Scatter effects are reduced in a radiographic imaging device, such as a digital slot scan mammographic imaging device, by reducing detected scatter and processing detector information to compensate for scatter effects. Spatial intensity profile information together with other imaging signal and patient dependent parameters can be used in image processing to estimate and compensate for various scatter effects including single and multiple scatters and Compton and Rayleigh scatter.

Abstract: According to the present invention, provided are an image discrimination apparatus and an image discrimination method for determining whether diaphragmatic radiation has been employed to obtain an autoradiograph of an object using a radiographic device having a diaphragmatic radiation function. According to the image discrimination apparatus and the image discrimination method of the present invention, an autoradiographic signal is entered and a first characteristic value is calculated using an autoradiograph designated by the autoradiographic signal, and then a frequency is calculated for the appearance of a density value for pixels constituting the edge of the autoradiograph that is determined using the first characteristic value and the frequency is employed to determine whether the autoradiograph has been obtained by using diaphragmatic radiation.

Abstract: An imaging system is disclosed for use in low-light environments or environments where low-levels of such radiation is desirable. Examples of such environments are night photography, laparoscopy, and mammography. In the case of radiation that is other than visible light, a radiation converter and method for fabricating same is disclosed. The radiation converter comprises a film of heavy scintillator (e.g. CdWO4) coated on a fiber optical window to efficiently convert the radiation into visible light. The visible light is passed into a signal amplifier employing an electron-bombarded charge-couple device (EBCCD) to amplify the signal. Novel methods of performing three-dimension imaging using this system as well as removing the effects of high speed movement are also disclosed.

Abstract: An apparatus and method are provided for determining whether diaphragmatic radiation has been employed to obtain an autoradiograph of an object using a radiographic device having a diaphragmatic radiation function. An autoradiographic signal is entered and a first characteristic value is calculated using an autoradiograph designated by the autoradiographic signal, and then a frequency is calculated for the appearance of a density value for pixels constituting the edge of the autoradiograph that is determined using the first characteristic value and the frequency is employed to determine whether diaphragmatic radiation was used.

Abstract: It is an object of one of the inventions to acquire a radiation image in which a stripe pattern originating from a scattered ray removing grid is less apt to interfere with observation. An image acquisition apparatus of one of the inventions includes a sensor for spatially sampling a radiation transmission distribution of an object to be imaged at a spatial sampling interval and acquiring an image of the object, and a scattered ray removing grid for removing scattered rays from the object, wherein an interval of elements of the scattered ray removing grid is set such that a spatial frequency of a stripe pattern, in the image, which originates from the scattered ray removing grid becomes not greater than 40% of a sampling frequency that is a reciprocal of the spatial sampling interval.

Abstract: In order to remove a scattered line component resulting from an object from projection data to obtain a satisfactory rearrangement image, an amount of scattered line is calculated from a region in which a first-order X-ray is shielded by an X-ray shield and a component corresponding to the scattered line is removed. Then, an image in the region in which the first-order X-ray is shielded is complemented based on an image taken from a 180-degree opposite direction.

Abstract: It is an object of one of the inventions to acquire a radiation image in which a stripe pattern originating from a scattered ray removing grid is less apt to interfere with observation. An image acquisition apparatus of one of the inventions includes a sensor for spatially sampling a radiation transmission distribution of an object to be imaged at a spatial sampling interval and acquiring an image of the object, and a scattered ray removing grid for removing scattered rays from the object, wherein an interval of elements of the scattered ray removing grid is set such that a spatial frequency of a stripe pattern, in the image, which originates from the scattered ray removing grid becomes not greater than 40% of a sampling frequency that is a reciprocal of the spatial sampling interval.

Abstract: A method of estimating an asymmetrical scatter signal distribution wherein asymmetry is introduced by angular incidence of radiation, which has been emitted from a source and transmitted through an object to be imaged, on a detector, is disclosed. This method includes, in an embodiment, modifying scatter that would be derived wherein the radiation is directly incident on the detector with zero degrees of inclination, using an asymmetry factor which indicates the shape and magnitude of the scatter signal distribution and which varies with an angle at which the radiation is incident on the detector, a mean attenuation coefficient of the object, and a distance the radiation has traveled through the object. The estimated scatter provides for correction of scatter in a image.

Abstract: It is an object of one of the inventions to acquire a radiation image in which a stripe pattern originating from a scattered ray removing grid is less apt to interfere with observation. An image acquisition apparatus of one of the inventions includes a sensor for spatially sampling a radiation transmission distribution of an object to be imaged at a spatial sampling interval and acquiring an image of the object, and a scattered ray removing grid for removing scattered rays from the object, wherein an interval of elements of the scattered ray removing grid is set such that a spatial frequency of a stripe pattern, in the image, which originates from the scattered ray removing grid becomes not greater than 40% of a sampling frequency that is a reciprocal of the spatial sampling interval.

Abstract: In cone-beam volume computed tomography or similar imaging techniques, the effects of x-ray scatter are reduced through using a beam compensation filter (a bow tie filter), air gap technique, and an antiscatter grid and corrected through the use of a beam stop array combined with interpolation or convolution operation. Images are taken with the beam stop array, and a larger number of images are taken without the beam stop array. The images taken with the beam stop array are spatially interpolated to derive scatter information, which is then angularly interpolated to provide as many scatter images as there are images taken without the beam stop array. The interpolations are performed through cubic spline interpolation or any other interpolation techniques or low-pass filtering operation (convolution operation with a selected kernel). Each scatter image is subtracted from a corresponding one of the images taken without the beam stop array to provide a sequence of scatter-corrected images.

Abstract: The radiography of a subject is improved by estimating the scattered radiation it transmits to the detectors. For this, one uses scattered radiation measured effectively through a simulacrum of the subject, with analogous attenuation properties, and which are modified by weighted coefficients obtained through a transformation of the values of total radiation received through the subject (3) and the simulacrum (8) selected. Thus it is also possible to improve radiographs without double irradiation of the subject to measure the scattered radiation separately.

Abstract: In recent years, x-ray imaging, which has been used to diagnose millions of illnesses and injuries, has evolved to use digital imaging instead of photographic film as a recording medium. Digital x-ray systems typically include an x-ray source, an x-ray focusing grid, and an array of light or x-ray detectors. Because of detector imperfections and other system factors, such as x-ray field non-uniformity and grid artifacts, digital x-ray images are often corrected, or compensated, before use. To this end, many digital x-ray systems include numerous application-specific correction maps, which unfortunately require regular maintenance that is not only time-consuming but expensive in terms of system downtime. Accordingly, the inventors devised new methods and systems for correcting application images that require maintenance of fewer correction maps. One exemplary implementation determines grid-only and non-grid correction maps and corrects application images based on a combination of these correction maps.

Abstract: A method and system for providing a portal image of an object utilizing a radiotheraphy system is disclosed. The radiotherapy system includes a system for providing at least one opening over the object. The at least one opening allows radiation therethrough. The method and system comprises acquiring a plurality of images through the at least one opening while moving the at least one opening over the object. Each of the plurality of images includes regions within the opening and regions outside the opening. The method and system includes obtaining a resulting portal image from the plurality of images. Radiation scattered to regions outside the opening is minimized in the resulting portal image to improve image quality. A method and system in accordance with the present invention utilizes a virtual grid to provide a resulting portal image with more contrast. The virtual grid is provided through an opening or a slit. The slit is preferably provided by a plate/jaw system in the radiotherapy system.

Abstract: The present invention provides an adaptive fluoroscopic noise reduction (FNR) algorithm utilizing various data acquisition parameters to generate an estimation of the noise statistics and to predict a minimal object contrast associated with the object. The estimation of the noise statistics and the prediction of the object contrast are then utilized to adapt certain variables that are utilized by the FNR algorithm. The estimation of noise statistics and the prediction of object contrast may be adapted on a pixel-by-pixel basis by using a regional mean to obtain an adapted estimation of noise statistics and an adapted prediction of object absolute contrast. The variables of the FNR algorithm are then adapted based on the adapted noise statistics estimation and the adapted prediction of object absolute contrast.

Abstract: An accessory for fluoroscopy equipment is provided to support the x-ray tube and detector on a pedestal with respect to a patient limb for quantitative bone densitometry measurement. Software loaded into the associated digital imaging fluoroscopy equipment provides necessary correction of the images for the quantitative accuracy needed for bone densitometry. Alternatively, a specialized detector or extremely low form factor image intensifier may be inserted in the pedestal to be used in lieu of the fluoroscopy equipment detector. A similar software correction is performed on an associated computer when a separate detector must be used.

Abstract: The unsharpness of a radiological image is estimated by four independent passes which recursively implement the same exponential function, and the unsharpness (Idk−1) estimated for the previous image (IMk−1) is subtracted from the current image (IMk).