Abstract: A computed tomography apparatus (10) includes spaced radiation sources (82, 84), such as anodes, which each propagate a cone-beam of radiation (40, 50) into an examination region (14). A detector (22) detects radiation which has passed through the examination region. An attenuation system (55) interposed between the radiation sources and the examination region for cone-angle dependent filtering of the cone beams. The attenuation system allows rays which contribute little to a reconstructed image to be attenuated more than rays which contribute more.

Abstract: CT scanners have a certain scan-field-of-view defined by the fan-angle of the system. According to an exemplary embodiment of the present invention, object points outside the scan-field-of-view may be reconstructed on the basis of a system of linear equations which may be solved iteratively and with reasonable effort. Therefore, explicit regularization techniques may be applied to recover the unknown object function.

Abstract: The invention relates to an apparatus for determining a high density region in an image, wherein the apparatus comprises a provision unit (1, 2, 6, 7, 8) for providing projection data for reconstructing the image. The apparatus comprises further a high density shadow determination unit (12) for determining a high density shadow in the projection data and a backprojection unit (13) for backprojecting the determined high density shadow resulting in a high density image showing the high density region. The inventions relates further to a corresponding method and computer program for determining a high density region in an image.

Abstract: It is described a filter (300) for at least partially compensating for an X-ray tube (10) the target angle heel effect and preserving the tungsten spectrum of the X-rays. The filter (300) has an anode side (302) and a cathode side (304), wherein the cathode side (304) has a higher attenuation coefficient than the anode side (302). The attenuation coefficient is determined to at least partially compensate for the target angle heel effect. The filter (300) is from the same material as an anode plate (110) or the anode (108) of the X-raysource (10) which is usually tungsten or a tungsten alloy.

Abstract: A scanning method and apparatus useful for correcting artifacts which may appear in a primary short circular CT scan are provided. A secondary helical scan performed on a stationary subject, or a secondary circular scan, may be used to correct for artifacts. The secondary scan may be performed with a smaller radiation dosage than the primary circular CT scan.

Abstract: According to the invention, there is provided a method of recording images of the heart in computer tomography, in which, in order to prevent movement artifacts, the images are reconstructed on the basis of similar movement states of the heart and different radiation intensities are used for different movement states. Also provided is a computer tomograph for recording images of the heart in computer tomography by means of time windows which exhibit similar movement states of the heart in order to prevent movement artifacts, said computer tomograph comprising a control device which controls a radiation source with different radiation intensities for different movement states.

Abstract: A computer tomography apparatus and method, a computer-readable medium and a program element are provided for examining a region of interest (ROI) of an object or patient in real-time. When only a region of interest is to be reconstructed, it is sufficient to rotate the radiation source and detector elements such that they cover a circular arc whose extension is less than ?+?, ? being the beam angle of the radiation source. This scanning range is called super-short-scan. Super-short-scans produce less data. Consequently image reconstruction is quicker which is very preferable for real-time CT. The CT data can furthermore be weighted in a manner that data detected at the end of a super-short-scan are weighted stronger than data detected at the beginning of a super-short-scan.

Abstract: It is described an X-ray tube (205), in particular for use in computed tomography, comprising an electron source (250), for generating an electron beam (255), an electron deflection device (256) for deflecting the generated electron beam (255), a control unit (257) being coupled to the electron deflection device (256) for spatially controlling the deflection, and an anode (206), which is arranged such that the electron beam (255) impinges onto a focal spot of a surface of the anode (206). Thereby the anode (206) is movable along a z-axis in an oscillating manner, the surface of the anode (206) is oriented oblique with respect to the z-axis, and the control unit (257) is adapted to spatially control the focal spot (255 a) in such a manner that the focal spot moves essentially in a discrete manner between a first focal spot position (106a, 406a) having a first z-coordinate and a second focal spot position (106b, 406b) having a second z-coordinate being different from the first z-coordinate.

Abstract: Known reconstruction techniques from coherent scattered x-rays apply non-exact reconstruction techniques. According to the present invention, a relatively wide spectrum of wave-vector transfers q of the scattered x-ray photons is acquired. The projection data is interpreted as line integrals in the x y-q space and the projection data is resorted to correspond to an acquisition along any source trajectory. Due to this, an exact helical reconstruction algorithms may be applied and redundant data may be used to obtain a better image quality.

Abstract: A reconstruction method for an image of an object, the reconstruction method comprising receiving a first projection data set representing information about said object, receiving a second projection data set representing information about said object, reconstructing a first image of said object using the first projection data set, reconstructing a second image of said object using the second projection data set, performing a registration between the first image and the second image, and fusing the first image and the second image to said image of said object, wherein the first projecting data set and the second projecting data set are achieved by using a single radiation type.

Abstract: Since the soft tissue levels in an image usually comprise a variety of values between air and bone boundaries, it may not be obvious a priori what threshold value applies. According to an exemplary embodiment of the present invention, an examination apparatus is provided which is adapted for determining the optimal weight for subtraction of a soft tissue correction image without performing a multitude of forward and backward projections. This may be provided determining a roughness function based on a plurality of subtractions of the soft tissue streak image, each subtraction corresponding to a different weighting of the streak image.

Abstract: CT scanners have a certain scan-field-of-view defined by the fan-angle of the system. According to an exemplary embodiment of the present invention, object points outside the scan-field-of-view may be reconstructed on the basis of a system of linear equations which may be solved iteratively and with reasonable effort. Therefore, explicit regularization techniques may be applied to recover the unknown object function.

Abstract: The invention relates to a method of computed tomography wherein a radiation source moves relative to an examination zone along a helical trajectory and wherein the movement involves a rotation around a rotational axis and a shifting parallel to the rotational axis. During the movement, a detector unit acquires real measured values. Fictitious measured values are determined from the real measured values by solving John's equation for a virtual movement of the radiation source along an intersection ellipse. The intersection ellipse intersects the helical trajectory at an intersection point and is the intersection of a virtual cylindrical surface, on which the helical trajectory is situated, with an intersection plane that is defined by a tangent vector of the helical trajectory at the intersection point and a vector that is oriented perpendicular to the rotational axis. Finally, an image of the examination zone is reconstructed using the real and fictitious measured values.

Abstract: The invention relates to a method of computed tomography wherein a radiation source moves relative to an examination zone along a helical trajectory and wherein the movement involves a rotation around a rotational axis and a shifting parallel to the rotational axis. During the movement, a detector unit acquires real measured values. Fictitious measured values are determined from the real measured values by solving John's equation for a virtual movement of the radiation source along an intersection ellipse. The intersection ellipse intersects the helical trajectory at an intersection point and is the intersection of a virtual cylindrical surface, on which the helical trajectory is situated, with an intersection plane that is defined by a tangent vector of the helical trajectory at the intersection point and a vector that is oriented perpendicular to the rotational axis. Finally, an image of the examination zone is reconstructed using the real and fictitious measured values.

Abstract: The invention relates to a computed tomography method in which a radiation source moves relative to an object on a helical trajectory, where the movement comprises a rotation around an axis of rotation and a displacement parallel to the axis of rotation. During the movement real measured values are acquired by means of a detector unit. First a provisional object image is constructed from the real measured values, from which provisional object image fictitious, non-acquired measured values can be determined by deriving the provisional object image in a direction parallel to the axis of rotation. An image of the examination area is reconstructed from the real and fictitious measured values.

Abstract: Known reconstruction techniques from coherent scattered x-rays apply non-exact reconstruction techniques. According to the present invention, a relatively wide spectrum of wave-vector transfers q of the scattered x-ray photons is acquired. The projection data is interpreted as line integrals in the x y-q space and the projection data is resorted to correspond to an acquisition along any source trajectory. Due to this, an exact helical reconstruction algorithms may be applied and redundant data may be used to obtain a better image quality.

Abstract: A steering system for a boat includes an auxiliary rudder which is rotatable to effect changes in course of the boat. A servo-pendulum rudder is rotatable by a positioning device. When the servo-pendulum rudder is rotated, it is pivotal transversely to a keel line of the boat by water flowing past the boat. A drive connection is provided between the servo-pendulum rudder and the auxiliary rudder. The drive connection includes a drive member and a driven member. One of the driving and driven members is pivotal between an engaged condition in which the drive connection is effective to transmit force between the pendulum rudder and the auxiliary rudder and disengaged condition in which the drive connection is ineffective to transmit force. The drive and driven members may be provided with teeth which are disposed in meshing engagement when the one of the driving and driven members is in the engaged condition.

Abstract: A mounting device for mounting a self-steering system on the stern (40) of a boat at a predefined angle determined from the stern configuration and a desired inclination of the self-steering system, comprises a supporting structure (10) for retaining and connecting the self-steering system with a pair of mounting brackets (20A, 20B) for retaining and connecting the supporting structure (10) with the stern of a boat (40), in which the mounting brackets (20A, 20B) have two first elongated holes (21, 22) extending along at least one approximately circular line for clamping the supporting structure (10) fast with at least four threaded bolts or the like such that its angle can be adjusted.

Abstract: A mounting device for mounting self-steering systems, bathing ladders or other accessories on the stern of boats comprising forked clamps having a front and a rear clamp limb which are integrally connected to each other at their root and which forked clamps having an opening for receiving a connecting means which exerts the clamping effect for connecting the clamp with the stern of the boat and, an elongate receiving zone for receiving and clamping a rail-like retaining element in a position such that it is matched in terms of position and angle between the clamp limb and an element or profiled bar having or forming at least one rail-like enlargement, which enlargement is matched to the elongate receiving zones of the forked clamp such that the enlargement can be inserted into the receiving zone of the forked clamp and can be adjusted and clamped fast in a position by the corresponding forked clamp.