Abstract: In one example embodiment, a method of volumetric image reconstruction of an examination region includes directing x-rays from an anode of an x-ray device towards the examination region from multiple positions relative to the examination region, including multiple focal spot positions radially shifted relative to the anode. X-rays that have passed through the examination region are detected and first multiple x-ray attenuation values are determined for each of the multiple positions. The first multiple x-ray values are based at least in part on the detected x-rays. Second multiple x-ray attenuation values associated with multiple levels are determined. The second multiple attenuation values are based at least in part on the first multiple attenuation values and the multiple positions. The method further includes generating a volumetric image reconstruction of the examination region based at least in part on the second multiple x-ray attenuation values.

Abstract: In one example embodiment, a method of volumetric image reconstruction of an examination region includes directing x-rays from an anode of an x-ray device towards the examination region from multiple positions relative to the examination region, including multiple focal spot positions radially shifted relative to the anode. X-rays that have passed through the examination region are detected and first multiple x-ray attenuation values are determined for each of the multiple positions. The first multiple x-ray values are based at least in part on the detected x-rays. Second multiple x-ray attenuation values associated with multiple levels are determined. The second multiple attenuation values are based at least in part on the first multiple attenuation values and the multiple positions. The method further includes generating a volumetric image reconstruction of the examination region based at least in part on the second multiple x-ray attenuation values.

Abstract: A medical imaging system (100) includes a radiation source (112) that rotates around an examination region about a longitudinal axis and emits radiation while translating in a direction of the longitudinal axis during a fly-by scan. A source collimator (114) collimates the emitted radiation during the fly-by scan to form a generally conical shaped radiation beam that traverses the examination region. The source collimator (114) dynamically varies collimation during the scan so as to increase and decrease a width of the radiation beam in the longitudinal axis direction during the scan. A detector array (122) detects radiation that traverses the examination region and generates signals indicative thereof. A reconstructor (126) reconstructs the signals to generate volumetric image data indicative of the examination region.

Abstract: A medical imaging system includes a generally stationary gantry (102) and a rotating gantry (106), rotatably supported by the generally stationary gantry (102), that rotates about a longitudinal axis around an examination region. The medical imaging system further includes a radiation source (112) that emits a radiation beam that traverses the examination region. The radiation source (112) is moveably affixed to the rotating gantry (106) so as to translate in a direction of the longitudinal axis with respect to the rotating gantry (106) while scanning a subject in the examination region. The medical imaging system further includes a detector array (120) that detects the radiation beam that traverses the examination region and generates a signal indicative thereof. The detector array (120) is moveably affixed to the rotating gantry (106) so as to move in coordination with the radiation source (112) while scanning the subject in the examination region.

Abstract: An imaging system includes a radiation source (110) with an anode (202). The radiation source (110) rotates around an examination region (106) about a longitudinal axis (108) and emits radiation from a focal spot (206) on the anode (202). A source collimator (112) collimates the emitted radiation to produce a generally conically shaped radiation beam that traverses the examination region. The generally conically shaped radiation beam has an extended cone angle along the longitudinal axis that is greater than an effective maximum cone angle determined by an anode angle of the anode (202). A detector array (116) detects radiation that traverses the examination region and generates signals indicative thereof. A reconstructor (118) reconstructs the signals to generate volumetric image data indicative of the examination region.

Abstract: When performing a fly-by or helical CT scan of a subject, radiation dose is limited by positioning a dynamic collimator (142) between the subject and an X-ray source (112). The collimator moves axially with the X-ray source (112) along a volume of interest (VOI) (122) in the subject and gradually opens, such that a narrow portion of the cone beam of X-rays is permitted to pass through the collimator (142) at ends of the VOI (122) and a wider full cone beam is emitted at central portions of the VOI (122). In this manner, tissue surrounding the VOI (122) is not needlessly exposed to X-rays, as would be the case if a full-width cone beam were used for the entire scan of the VOI (122).

Abstract: A computed tomography scanner (10) acquires prospectively gated cardiac projection data. A scan controller (42) causes the scanner (10) to acquire projection data at the predicted location of a target cardiac phase in a cardiac cycle of the patient. An error determiner (44) determines an error between the target phase and the phase at which the projection data was actually acquired. Depending on the error, the patient is rescanned in a subsequent cardiac cycle.

Abstract: An imaging system includes a radiation source (110) with an anode (202). The radiation source (110) rotates around an examination region (106) about a longitudinal axis (108) and emits radiation from a focal spot (206) on the anode (202). A source collimator (112) collimates the emitted radiation to produce a generally conically shaped radiation beam that traverses the examination region. The generally conically shaped radiation beam has an extended cone angle along the longitudinal axis that is greater than an effective maximum cone angle determined by an anode angle of the anode (202). A detector array (116) detects radiation that traverses the examination region and generates signals indicative thereof. A reconstructor (118) reconstructs the signals to generate volumetric image data indicative of the examination region.

Abstract: A computed tomography system (100) includes an x-ray source (112) that rotates about an examination region (108) and translates along a longitudinal axis (120). The x-ray source (112) remains at a first location on the longitudinal axis (120) while rotating about the examination region (108), accelerates to a scanning speed and performs a fly-by scan of a region of interest (220) in which at least one hundred and eighty degrees plus a fan angle of data is acquired. At least one detector (124) detects x-rays radiated by the x-ray source (112) that traverses the examination region (108) and generates signals indicative thereof. A reconstructor (132) reconstructs the signals to generate volumetric image data.

Abstract: A medical imaging system includes a generally stationary gantry (102) and a rotating gantry (106), rotatably supported by the generally stationary gantry (102), that rotates about a longitudinal axis around an examination region. The medical imaging system further includes a radiation source (112) that emits a radiation beam that traverses the examination region. The radiation source (112) is moveably affixed to the rotating gantry (106) so as to translate in a direction of the longitudinal axis with respect to the rotating gantry (106) while scanning a subject in the examination region. The medical imaging system further includes a detector array (120) that detects the radiation beam that traverses the examination region and generates a signal indicative thereof. The detector array (120) is moveably affixed to the rotating gantry (106) so as to move in coordination with the radiation source (112) while scanning the subject in the examination region.

Abstract: A medical imaging system (100) includes a radiation source (112) that rotates around an examination region about a longitudinal axis and emits radiation while translating in a direction of the longitudinal axis during a fly-by scan. A source collimator (114) collimates the emitted radiation during the fly-by scan to form a generally conical shaped radiation beam that traverses the examination region. The source collimator (114) dynamically varies collimation during the scan so as to increase and decrease a width of the radiation beam in the longitudinal axis direction during the scan. A detector array (122) detects radiation that traverses the examination region and generates signals indicative thereof. A reconstructor (126) reconstructs the signals to generate volumetric image data indicative of the examination region.

Abstract: A computed tomography method includes rotating an electron beam along an anode (104) disposed about an examination region (112) for a plurality of sampling intervals in which x-ray projections are sampled. The electron beam is swept during each sampling interval to generate a plurality of successive focal spots at different focal spot locations during each sampling interval, wherein the focal spots generated in a given sampling interval include a sub-set of the focal spots generated in a previous sampling interval. The x-ray projections radiated from each of the plurality of focal spots is sampled during each sampling interval. The resulting data is reconstructed to generate volumetric image data.

Abstract: When performing an interventional CT scan on a subject, radiation dose is limited by employing a dynamic collimator (142) that collimates X-rays emitted by an X-ray source (112). The X-ray source (112) and collimator (142) rotate around a VOI (122) in the subject, and move axially along the VOI (122) to maintain the tip of a medical instrument (144) within the field of view of the narrow cone beam. An instrument tracking component (146) maintains information related to previous and current positions of the instrument (144) relative to the VOI (122) and facilitates tracking the instrument as it moves through the VOI (122). A user interface (136) superimposes images of a sub-region of the VOI (122) in which the instrument tip is located onto a pre-generated diagnostic image for viewing by an operator, to track the medical instrument (144).

Abstract: When performing a fly-by or helical CT scan of a subject, radiation dose is limited by positioning a dynamic collimator (142) between the subject and an X-ray source (112). The collimator moves axially with the X-ray source (112) along a volume of interest (VOI) (122) in the subject and gradually opens, such that a narrow portion of the cone beam of X-rays is permitted to pass through the collimator (142) at ends of the VOI (122) and a wider full cone beam is emitted at central portions of the VOI (122). In this manner, tissue surrounding the VOI (122) is not needlessly exposed to X-rays, as would be the case if a full-width cone beam were used for the entire scan of the VOI (122).

Abstract: A computed tomography scanner (10) acquires prospectively gated cardiac projection data. A scan controller (42) causes the scanner (10) to acquire projection data at the predicted location of a target cardiac phase in a cardiac cycle of the patient. An error determiner (44) determines an error between the target phase and the phase at which the projection data was actually acquired. Depending on the error, the patient is rescanned in a subsequent cardiac cycle.

Abstract: A radiographic imaging apparatus includes a radiation detector (16) and a radiation source (12) which projects a non-parallel beam of radiation into field of view (14). A footprint of each voxel (v) which is projected on the detector (16) is corrected based on the position of the voxel (v) in the field of view (14) in relation to the radiation detector (16) and the radiation source (12). The contributions from substantially parallel redundant projections are further combined based on a fractional distance frac from a center point (82) of the voxel (v) to a center of each of the adjacent redundant projections.

Abstract: A computed tomography method includes rotating an electron beam along an anode (104) disposed about an examination region (112) for a plurality of sampling intervals in which x-ray projections are sampled. The electron beam is swept during each sampling interval to generate a plurality of successive focal spots at different focal spot locations during each sampling interval, wherein the focal spots generated in a given sampling interval include a sub-set of the focal spots generated in a previous sampling interval. The x-ray projections radiated from each of the plurality of focal spots is sampled during each sampling interval. The resulting data is reconstructed to generate volumetric image data.

Abstract: A computed tomography system (100) includes an x-ray source (112) that rotates about an examination region (108) and translates along a longitudinal axis (120). The x-ray source (112) remains at a first location on the longitudinal axis (120) while rotating about the examination region (108), accelerates to a scanning speed and performs a fly-by scan of a region of interest (220) in which at least one hundred and eighty degrees plus a fan angle of data is acquired. At least one detector (124) detects x-rays radiated by the x-ray source (112) that traverses the examination region (108) and generates signals indicative thereof. A reconstructor (132) reconstructs the signals to generate volumetric image data.

Abstract: A radiographic imaging apparatus includes a radiation detector (16) and a radiation source (12) which projects a non-parallel beam of radiation into field of view (14). A footprint of each voxel (v) which is projected on the detector (16) is corrected based on the position of the voxel (v) in the field of view (14) in relation to the radiation detector (16) and the radiation source (12). The contributions from substantially parallel redundant projections are further combined based on a fractional distance frac from a center point (82) of the voxel (v) to a center of each of the adjacent redundant projections.

Abstract: A tomographic apparatus (10) includes radiation source (20), at least one radiation sensitive detector (30), and a reconstruction system (40). The radiation source (20) sweeps along a z-axis (16) and returns to its initial position in coordination with about two revolutions of the radiation source (20) about an imaging region (32) with a frequency of about half a frequency of a revolution of the radiation source (20) about the imaging region (32). The at least one radiation sensitive detector (30) detects radiation emitted by the radiation source (20) that traverses a volume of interest (52) within the imaging region (32) and generates data indicative of the detected radiation. The reconstruction system (40) reconstructs the detected data to generate an image of a subject in the volume of interest (52).