Abstract: The invention relates to a computer tomography method, in which a periodically moving object, especially a heart, is irradiated by a beam bundle. In that process, intermediate images of one and the same subregion of the object are reconstructed using measured values from time intervals from different periods. That is, in each case exactly one period can be allocated to each intermediate image. The time intervals in the individual periods are adjusted in such a way that, after a reconstruction of the intermediate images using measured values that lie in the adjusted time intervals, a similarity measure applied to the intermediate images of the same subregion is minimized. This method can be applied to one, several or all subregions of the object that are reconstructable using measured values from time intervals from different periods. Finally, a computer tomography image is reconstructed, wherein exclusively measured values from the adjusted time intervals are used.

Abstract: A computed tomography scanner includes a rotating gantry (20) defining an examination region (16). A first radiation source (22) is disposed on the rotating gantry (20) and emits first radiation (32) into the examination region (16). A second radiation source (24) is disposed on the rotating gantry (20) and emits second radiation (36) into the examination region (16). The second radiation source (24) is angularly spaced around the gantry from the first radiation source (22). A first radiation detector (30, 30?) receives the first radiation (32). A center of the first radiation detector (30, 30?) is angularly spaced around the gantry from the first radiation source (22) by less than 180°. A second radiation detector (34) receives the second radiation (36). A center of the second radiation detector (34) is angularly spaced around the gantry from the second radiation source (24) by less than 180°.

Abstract: A computed tomography imaging system includes an x ray tube (12, 212) that injects an x ray conebeam into an examination region (14). The x ray tube (12, 212) includes a rotating cylindrical anode (30, 230, 330, 430) having a target outer surface region. The cylindrical anode (30, 230, 330, 430) rotates about a longitudinally aligned cylinder axis (32). Electrons are accelerated toward a selected spot on the target outer surface region of the cylindrical anode (30, 230, 330, 430). Electrostatic or electromagnetic deflectors (64, 68) sweep the selected spot back and forth across the target outer surface region of the cylindrical anode (30, 330, 430). The imaging system further includes a rotating gantry (22) that revolves the x ray tube (12, 212) about the examination region (14) around a rotation axis that is parallel to the cylindrical axis, and an x-ray detector (16) arranged to detect x rays after said x rays pass through the examination region (14).

Abstract: In a diagnostic cardiac imaging session of a patient's heart using a computed tomography imaging scanner (10) and a cardiac cycle monitor (42), a diagnostic objective (100) is received. Survey imaging (104) of the heart is performed to determine optimized imaging parameter values for the received diagnostic objective (100). Monitor imaging (108) of a limited portion of the heart is performed during influx of a contrast agent (22) using a low patient x-ray exposure condition to detect a trigger condition. Volume imaging (110) of the heart responsive to detection of the trigger condition is performed using the optimized imaging parameter values to obtain volumetric imaging data. Cardiac cycle data is recorded during at least a portion of the survey imaging (104), the monitor imaging (108), and the volume imaging (110). High resolution reconstructing (130) of at least some volumetric imaging data is performed to produce high resolution image representations (132).

Abstract: A conebeam computed tomography scanner (10) acquires conebeam projection data along a generally helical source trajectory around an examination region (14). An exact reconstruction processor (40) includes a convolution processor (42) and an aperture weighted backprojection processor (46, 66). The convolution processor (42) performs at least one convolution of the acquired projection data. The convolving operates on projection data falling within an exact reconstruction window (38) and on at least some redundant projection data falling outside the exact reconstruction window (38) to produce convolved projection data.

Abstract: An apparatus for computed tomography (CT) imaging of a cyclically moving organ includes a positional state monitor (24, 40) that monitors a positional state of the cyclically moving organ such as the heart. A cone-beam CT scanner (10) acquires image data at least within a plurality of time windows. Each time window is centered about an occurrence of a selected positional state of the organ. A window analyzer (38) selects a data segment within each time window such that the data segments combine to form a complete data set covering a selected angular range. A reconstruction processor (44) reconstructs the selected data segments into an image representation.

Abstract: A computed tomography imaging scanner (10) acquires helical cone beam projection data for a volume of interest (46) using at least two source trajectory helices. A reconstruction processor (62) reconstructs the projection data for each helix to generate a corresponding time skewed image representation. A voxel time processor (66) computes an acquisition time for each voxel in each time skewed image representation. A voxel interpolator (68) computes an interpolated voxel value for each voxel based on values of the voxel in the time skewed image representations and corresponding voxel acquisition times. In an electronic embodiment, the computed tomography scanner (10) includes an x-ray source (12) with an axially oriented cylindrical anode (92), an electron source (961, 962) irradiating the cylindrical anode (92) to produce an x-ray beam (120, 122, 124, 126), and an electron beam deflector (98, 100) that deflects the electron beam along the anode (92) to axially sweep the x-ray beam.

Abstract: An image reconstruction method for reconstructing cone or wedge-beam computed tomography projection data includes re-binning (50) the projection data to associate projection data having the similar angular orientation (&thgr;), weighting (60) projection data based on at least one of its angular orientation (&thgr;) and its location within a detector aperture (20), and reconstructing (66) the weighted projection data (64) to form a volume image representation (70). In one preferred embodiment, the weighting (60) includes distributing (56) re-binned projection data (52) associated with a selected image element which one of (a) has the same angular orientation (&thgr;) and (b) is angularly separated by integer multiples of 180° into a selected one or more of a plurality of parallel processing pipelines (60m), and combining (62) the outputs of the selected one or more parallel processing pipelines (60m) to produce weighted projection data (64).

Abstract: In a diagnostic cardiac imaging session of a patient's heart using a computed tomography imaging scanner (10) and a cardiac cycle monitor (42), a diagnostic objective (100) is received. Survey imaging (104) of the heart is performed to determine optimized imaging parameter values for the received diagnostic objective (100). Monitor imaging (108) of a limited portion of the heart is performed during influx of a contrast agent (22) using a low patient x-ray exposure condition to detect a trigger condition. Volume imaging (110) of the heart responsive to detection of the trigger condition is performed using the optimized imaging parameter values to obtain volumetric imaging data. Cardiac cycle data is recorded during at least a portion of the survey imaging (104), the monitor imaging (108), and the volume imaging (110). High resolution reconstructing (130) of at least some volumetric imaging data is performed to produce high resolution image representations (132).

Abstract: A computed tomography imaging scanner (10) acquires helical cone beam projection data for a volume of interest (46) using at least two source trajectory helices. A reconstruction processor (62) reconstructs the projection data for each helix to generate a corresponding time skewed image representation. A voxel time processor (66) computes an acquisition time for each voxel in each time skewed image representation. A voxel interpolator (68) computes an interpolated voxel value for each voxel based on values of the voxel in the time skewed image representations and corresponding voxel acquisition times. In an electronic embodiment, the computed tomography scanner (10) includes an x-ray source (12) with an axially oriented cylindrical anode (92), an electron source (961, 962) irradiating the cylindrical anode (92) to produce an x-ray beam (120, 122, 124, 126), and an electron beam deflector (98, 100) that deflects the electron beam along the anode (92) to axially sweep the x-ray beam.

Abstract: An image reconstruction method for reconstructing cone or wedge-beam computed tomography projection data includes re-binning (50) the projection data to associate projection data having the similar angular orientation (&thgr;), weighting (60) projection data based on at least one of its angular orientation (&thgr;) and its location within a detector aperture (20), and reconstructing (66) the weighted projection data (64) to form a volume image representation (70). In one preferred embodiment, the weighting (60) includes distributing (56) re-binned projection data (52) associated with a selected image element which one of (a) has the same angular orientation (&thgr;) and (b) is angularly separated by integer multiples of 180° into a selected one or more of a plurality of parallel processing pipelines (60m), and combining (62) the outputs of the selected one or more parallel processing pipelines (60m) to produce weighted projection data (64).

Abstract: Data collected from a cone beam scanner is reconstructed into a volumetric image representation by defining a plurality of oblique surfaces which are reconstructed into a cylinder. An interpolator identifies non-redundant rays of radiation passing through the surfaces. Rays of radiation intersecting a center point of each oblique surface are identified along with rays tangent to surface rings on each surface. Data from the identified non-redundant rays is weighted by a first processor. A second processor convolves the weighted data and passes it to a backprojector which backprojects it into an image memory. The oblique surface reconstruction technique facilitates use of conventional two-dimensional convolution and backprojection techniques that enjoy relative computational simplicity and efficiency as well as three-dimensional reconstruction techniques that use a minimum number of projections.

Abstract: A method of cardiac gating for use in an imaging apparatus includes monitoring a patient's cardiac cycle, and determining a cardiac cycle time for the patient. A desired cardiac phase of interest is selected, and a delay from a reference point in the cardiac cycle is determined. The delay is a function of the selected cardiac phase and the cardiac cycle time. Finally, the selected cardiac phase is located in the cardiac cycle using the delay. This cardiac gating method compensates for non-uniform changes in the patient's cardiac cycle corresponding to a non-uniform distribution of cardiac phases in the patient's cardiac cycle.

Abstract: An apparatus for computed tomography (CT) imaging of a cyclically moving organ includes a positional state monitor (24, 40) that monitors a positional state of the cyclically moving organ such as the heart. A cone-beam CT scanner (10) acquires image data at least within a plurality of time windows. Each time window is centered about an occurrence of a selected positional state of the organ. A window analyzer (38) selects a data segment within each time window such that the data segments combine to form a complete data set covering a selected angular range. A reconstruction processor (44) reconstructs the selected data segments into an image representation.

Abstract: Data collected from a cone beam scanner is reconstructed into a volumetric image representation by defining a plurality of oblique surfaces (44) which are reconstructed into a reconstruction cylinder (C). An interpolator (52) identifies non-redundant rays of radiation which pass through the oblique surfaces. More particularly, rays of radiation that intersect a center point of each oblique surface (70) are identified along with rays tangent to surface rings on each oblique surface (72, 74). Data from the identified non-redundant rays of radiation is weighted by a first data processor (54). A second data processor (56) convolves the weighted data and passes it to a backprojector (58) which backprojects the data into an image memory (60).

Abstract: Data collected from a cone beam scanner is reconstructed by defining a plurality of oblique surfaces (44) which are reconstructed into a reconstruction cylinder (C). An interpolator (52) identifies non-redundant rays that intersect a center point of each oblique surface (70) along with rays tangent to surface rings on each oblique surface (72, 74). Data from the non-redundant rays is weighted by a first data processor (54). A second data processor (56) convolves the weighted data and passes it to a backprojector (58) which backprojects the data into an image memory (60). The oblique surface reconstruction technique facilitates the use of conventional two-dimensional convolution and backprojection techniques that enjoy relative computational simplicity and efficiency as well as three-dimensional reconstruction techniques that use a minimum number of projections.

Abstract: A needle biopsy system (10) includes a biopsy needle (210), and a needle support assembly (200). The needle support assembly (200) holds the biopsy needle (210) and manipulates the biopsy needle (210) in response to received control signals. A needle simulator (250) having an input device (252) generates the control signals in response to manipulation of the input device (252) by an operator. The operator, in turn, receives feedback from the needle simulator (250) in accordance with forces experienced by the biopsy needle (210). In a preferred embodiment, the feedback received by the operator includes tactile sensations experienced by the operator as the operator manipulates the input device (252). The tactile sensations mimic those the operator would have received had the operator directly manipulated the biopsy needle (210). Optionally, a curved needle guide (280) is employed to restrict the biopsy needle's progression longitudinally therethrough.

Abstract: A method of diagnostic image reconstruction from projection data is provided. It includes generating projection data followed by a convolution of the same. The convolved projection data is then scaled into unsigned, fixed precision words of a predetermined number of bits. The words are then split into a predetermined number of color channels corresponding to color channels of a multi-color rendering engine (150). Simultaneously and independently, the split words are backprojected along each of the color channels to obtain backprojected views for each color channel. The backprojected views for each color channel are accumulated to produce separate color images corresponding to each color channel. Finally, the separate color images are recombined to produce an output image. In a preferred embodiment, prior to the convolution of the projection data, a rebinning operation is performed to ensure that the projection data is in a parallel format.

Abstract: A patient supported on a patient support (12) is moved into a bore (22) of a planning imaging device, such as a CT scanner (20). A three-dimensional diagnostic image in three-dimensional diagnostic image space is generated and stored in a memory (130). The patient is repositioned outside of the bore with a region of interest in alignment with a real time imaging device, such as a fluoroscopic imaging device (40). A surgical planning instrument (60), such as a pointer or biopsy needle (62), is mounted on an articulated arm (64). As the instrument is inserted into the region of interest, fluoroscopic images are generated and stored in a memory (140). The coordinate systems of the CT scanner, the fluoroscopic device, and the surgical instrument are correlated (102, 104, 112, 120) such that the instrument is displayed on both the CT images (134) and the fluoroscopic images (50), such that cursors move concurrently along the fluoroscopic and CT images, and the like.

Abstract: A continuous CT scanner (10) for producing real time images includes a stationary gantry portion (12) having an examination region (14) and a rotating gantry portion (20) for continuous rotation about the examination region (14). Mounted to the rotating gantry portion (20) is an imaging x-ray source (22) which produces a fan-shaped x-ray beam (24) having a plurality of rays through the examination region (14). A plurality of radiation detectors (28) are mounted to one of the rotating and stationary gantry portions (20, 12) and are arranged to receive rays of the fan-shaped x-ray beam (24) after the rays have passed through the examination region (14). The plurality of radiation detectors (28) converts detected radiation into electronic data wherein the electronic data includes a plurality of data lines in a fan beam format. A rebinning processor (30) interpolates the electronic data from the fan-beam format to a parallel-beam format.