Abstract: Methods and systems for calibrating a Computed Tomography (CT) system are provided. The method includes selectively activating each of a plurality of elements of a detector in the CT system. The method further includes determining for each of the selectively activated elements, a crosstalk effect on elements adjacent to the activated elements, to calibrate the CT system.

Abstract: For the purpose of X-ray CT imaging a heart of a subject with high image quality while reducing stress on the subject, once an optimal cardiac phase has been set by an optimal cardiac phase setting section 30b and a target position in a subject to be scanned when the cardiac phase of the subject is at an optimal cardiac phase is defined at a target position defining section 30c, a transport-starting-cardiac-phase calculating section 30b calculates a transport-starting cardiac phase such that the target position is scanned at the optimal cardiac phase, using the optimal cardiac cycle, target position, scan start position, transport speed of an imaging table, and approach-run time for the imaging table. A scan control section starts transport at the imaging table 4 when the cardiac phase of the subject coincides with the transport-starting cardiac phase, and performs a helical scan with a helical pitch of one or more, for example.

Abstract: In X-ray CT imaging for scanning a subject in the same anatomical region with two kinds of X-rays having different energy distributions, for the purpose of reducing a subject's positional offset between two kinds of tomographic images representing the same slice by a simple control scheme while reducing stress on the subject, a cardiac cycle identifying section 30b identifies a cardiac cycle of a subject 6 by an electrocardiograph 5 or the like, and a scan start time interval setting section 30c sets a time interval from the start of a first scan with first X-rays to the start of a second scan with second X-rays to a time approximately the same as the aforementioned cardiac cycle. A scan control section 30a controls several sections to keep a constant rotation speed of a rotating section 27 and start the scans at the aforementioned time interval. In each scan, projection data over a given view angle sufficient for reconstruction processing for a tomographic image are collected at once.

Abstract: The present invention provides an X-ray CT apparatus for imaging an MD image having a better S/N. The X-ray CT apparatus for taking an image with one of two materials within a subject to be examined being fractionated, acquiring two sets of data corresponding to said two types of X-ray having different energy by scanning using said two types of X-ray, generating a first image based on the two sets of data with the pixel values made by weighted addition of two types of CT values corresponding to the two types of X-ray, generating a second image based on the two sets of data, wherein the other one of the two types of material being fractionated, and generating an image by weighted subtraction of the first image and the second image.

Abstract: An X-ray CT apparatus includes an X-ray radiation unit which applies a first X-ray having a first energy spectrum and a second X-ray having a second energy spectrum different from the first energy spectrum to a subject, an X-ray data acquisition unit which acquires first X-ray projection data of the subject based on the first X-ray and second X-ray projection data of the subject based on the second X-ray, and an image reconstruction unit which determines information about a difference between the first X-ray and the second X-ray with respect to an image of the subject, segments the image into at least two pixel areas based on the difference information, and sets part of the segmented pixel areas to a dual energy image obtained by a weighted subtraction process based on X-ray projection data having a plurality of energy spectrums.

Abstract: An X-ray CT apparatus includes an X-ray data acquisition device for acquiring X-ray projection data transmitted through a subject lying between an X-ray generator and an X-ray detector having a two-dimensional detection plane and detecting X rays in opposition to the X-ray generator, while the X-ray generator and the X-ray detector are being rotated about a center of rotation lying there between; an image reconstructing device for image-reconstructing the acquired projection data; an image display device for displaying the image-reconstructed tomographic image; and an imaging condition setting device for setting various kinds of imaging conditions for tomographic image, wherein the X-ray data acquisition device acquires X-ray projection data in sync with an external sync signal by a helical scan with a predetermined range of the subject with a helical pitch set to 1 or more.

Abstract: An image display system includes a display device, an input section to which video signals of an interlace scanning system are inputted, a signal converter section which increases horizontal scanning lines of the inputted video signals in number by a factor of at least two, and which generates first and second fields, each of the fields including effective scanning lines used for displaying and ineffective scanning lines not used for displaying, with the effective and ineffective scanning lines being arranged alternately in each of the fields, and a display control section which controls the display device to display the first and second fields alternately. The display control section controls the display device such that positions of the effective scanning lines of the first fields correspond with those of the ineffective scanning lines of the second fields, and vice versa.

Abstract: The present invention provides an X-ray CT apparatus for imaging an MD image having a better S/N. The X-ray CT apparatus for taking an image with one of two materials within a subject to be examined being fractionated, acquiring two sets of data corresponding to said two types of X-ray having different energy by scanning using said two types of X-ray, generating a first image based on the two sets of data with the pixel values made by weighted addition of two types of CT values corresponding to the two types of X-ray, generating a second image based on the two sets of data, wherein the other one of the two types of material being fractionated, and generating an image by weighted subtraction of the first image and the second image.

Abstract: In X-ray CT imaging for scanning a subject in the same anatomical region with two kinds of X-rays having different energy distributions, for the purpose of reducing a subject's positional offset between two kinds of tomographic images representing the same slice by a simple control scheme while reducing stress on the subject, a cardiac cycle identifying section 30b identifies a cardiac cycle of a subject 6 by an electrocardiograph 5 or the like, and a scan start time interval setting section 30c sets a time interval from the start of a first scan with first X-rays to the start of a second scan with second X-rays to a time approximately the same as the aforementioned cardiac cycle. A scan control section 30a controls several sections to keep a constant rotation speed of a rotating section 27 and start the scans at the aforementioned time interval. In each scan, projection data over a given view angle sufficient for reconstruction processing for a tomographic image are collected at once.

Abstract: For the purpose of providing an X-ray tomographic imaging apparatus for displaying a dual-energy image to facilitate diagnosis by an operator, an X-ray tomographic imaging apparatus (10) comprises: an image comparison information calculating section (24) for calculating image comparison information between said first-energy projection dataset (LD) or first-energy tomographic image (LT) and said second-energy projection dataset (HD) or second-energy tomographic image (HT); a region-of-interest defining section (23) for defining a region of interest; a weighting factor determining section (25-2) for determining a weighting factor for use in weighted subtraction processing between said first-energy projection dataset or first-energy tomographic image and said second-energy projection dataset or second-energy tomographic image, such that said image comparison information in said region of interest can be substantially eliminated by conducting said weighted subtraction processing; and a dual-energy image reconstru

Abstract: For the purpose of X-ray CT imaging a heart of a subject with high image quality while reducing stress on the subject, once an optimal cardiac phase has been set by an optimal cardiac phase setting section 30b and a target position in a subject to be scanned when the cardiac phase of the subject is at an optimal cardiac phase is defined at a target position defining section 30c, a transport-starting-cardiac-phase calculating section 30b calculates a transport-starting cardiac phase such that the target position is scanned at the optimal cardiac phase, using the optimal cardiac cycle, target position, scan start position, transport speed of an imaging table, and approach-run time for the imaging table. A scan control section starts transport at the imaging table 4 when the cardiac phase of the subject coincides with the transport-starting cardiac phase, and performs a helical scan with a helical pitch of one or more, for example.

Abstract: The present invention is intended to improve image quality ensured by a conventional (axial) scan, a cine scan, or a helical scan performed by an X-ray CT apparatus including a two-dimensional area X-ray detector that has a matrix structure. In helical scan image reconstruction based in three-dimensional image reconstruction performed in an X-ray CT apparatus including a two-dimensional area X-ray detector that is represented by a multi-array X-ray detector or a flat-panel X-ray detector and that has a matrix structure, an image expressing a slice thickness larger than the width of one detector array included in a multi-array X-ray detector is reconstructed according to either of a method of convoluting a z-direction filter to projection data items in the direction of detector arrays (z direction) and a method of convoluting a filer to a tomographic image space in the z direction. The two methods are optimized in terms of a calculation time and tomographic image quality.

Abstract: A scan control method for an X-ray CT apparatus wherein a subject with a contrast agent injected therein is helically scanned with an X-ray beam and image reconstruction is performed based on projection data obtained through an X-ray detector. The method includes controlling a velocity of a helical scan following motion of the contrast agent in the subject.

Abstract: An X-ray CT apparatus includes an X-ray data acquisition device for acquiring X-ray projection data transmitted through a subject lying between an X-ray generator and an X-ray detector having a two-dimensional detection plane and detecting X rays in opposition to the X-ray generator, while the X-ray generator and the X-ray detector are being rotated about a center of rotation lying therebetween; an image reconstructing device for image-reconstructing the acquired projection data; an image display device for displaying the image-reconstructed tomographic image; and an imaging condition setting device for setting various kinds of imaging conditions for tomographic image, wherein the X-ray data acquisition device acquires X-ray projection data in sync with an external sync signal by a helical scan with a predetermined range of the subject with a helical pitch set to 1 or more.

Abstract: With the object of realizing an X-ray CT apparatus which performs a plurality of pieces of imaging small in resolution degradation too simultaneously while suppressing an expansion of a data acquisition section that receives an electric signal of an X-ray detector, such an array that X-ray detectors in a channel direction are operated with the two as one pair is made by first detector switching means of a switching unit. This array moved by one X-ray detector in the channel direction is alternately repeated in the row or channel direction. Therefore, even when the number of receivers is small, data extending over a wide imaging range can simultaneously be collected while the degradation of resolution is being suppressed to a minor degree. By extension, imaging more coincident with an operator-aimed image can be done by making the switching use of imaging in high resolution.

Abstract: For the purpose of providing an image projection method for incorporating all data values along a projection axis on a projection image produced from three-dimensional data, a pixel value G at a point of intersection of the projection axis and projection plane is determined as: G = ? ( ? i = 1 n ? ? V ? ? i / n ) r - ? i = 1 n ? ( ? V ? ? i / n ) r ? 1 / r , where the number of three-dimensional data values along the projection axis is denoted by n, a data value is denoted by Vi, and a real number greater than one is denoted by r.

Abstract: The present invention is intended to improve image quality ensured by a conventional (axial) scan, a cine scan, or a helical scan performed by an X-ray CT apparatus including a two-dimensional area X-ray detector that has a matrix structure. In helical scan image reconstruction based in three-dimensional image reconstruction performed in an X-ray CT apparatus including a two-dimensional area X-ray detector that is represented by a multi-array X-ray detector or a flat-panel X-ray detector and that has a matrix structure, an image expressing a slice thickness larger than the width of one detector array included in a multi-array X-ray detector is reconstructed according to either of a method of convoluting a z-direction filter to projection data items in the direction of detector arrays (z direction) and a method of convoluting a filer to a tomographic image space in the z direction. The two methods are optimized in terms of a calculation time and tomographic image quality.

Abstract: This invention provides an X-ray CT capable of presenting information of exposure to the operator by displaying X-ray dose information of each of regions of interest to be scanned by an X-ray CT apparatus, thereby encouraging reduction in exposure and optimization. X-ray dose information of each region to be scanned by a conventional scan (axial scan), a cine scan, a helical scan, or a variable-pitch helical scan of an X-ray CT apparatus is displayed so that the operator can recognize the X-ray dose information before acquisition of an image of a subject.

Abstract: When an X-ray CT apparatus including a two-dimensional X-ray area detector performs a conventional (axial) scan or a cine scan, a plurality of segments of projection data items detected synchronously with an external signal or a biomedical signal is sampled from projection data items acquired during one scan or a plurality of scans. Projection data items corresponding to those detected during a half scan of rotating an X-ray tube by an angle of 180° plus the angle of a fan beam falling on the detector or during a 360° full scan are used to reconstruct a three-dimensional image. Thus, a three-dimensional tomographic image enjoying a high temporal resolution is displayed. Moreover, successive three-dimensional display images showing states of a subject synchronized with respective phases of the external signal or biomedical signal may be displayed as a four-dimensional image.

Abstract: In an X-ray CT apparatus, radiographic conditions (protocols) for imaging of each position represented by a z-coordinate are optimized in relation to an X-ray cone beam that spreads in a z direction. A slice thickness of a tomographic image is freely controlled in the z direction using a z filter during a conventional scan or a cine scan. For each tomographic image, a reconstruction function, an image filter, a scan field, a tomographic-image tilt angle, and a position of a tomographic image are freely adjusted or independently designated for scanning of each position in the z direction. Thus, a tomographic image is reconstructed. Moreover, the position of a beam formation X-ray filter in the z direction is shifted in order to optimize a patient dose that depends on the size of the scan field, and X-ray quality.