Patents by Inventor Roland Proksa

Roland Proksa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • IMAGING SYSTEM FOR IMAGING A REGION OF INTEREST FROM ENERGY-DEPENDENT PROJECTION DATA
    Publication number: 20100091946
    Abstract: The invention relates to an imaging system for imaging a region of interest from energy-dependent projection data, wherein the imaging system comprises a projection data providing unit (1, 2, 3, 6, 7, 8) for providing energy-dependent first projection data of the region of interest. The imaging system comprises further an attenuation component image generation unit (12) for generating attenuation component images of the region of interest by generating energy-dependent second projection data using a model in which the projection data depend on attenuation component images. The component image generation unit (12) is adapted for generating the attenuation component images such that deviations of the second projection data from the first projection data are reduced.
    Type: Application
    Filed: April 17, 2008
    Publication date: April 15, 2010
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventor: Roland Proksa
  • CT IMAGING SYSTEM
    Publication number: 20100061504
    Abstract: The invention relates to a CT imaging system for determining the flow of a substance within an object, wherein the CT imaging system comprises a polychromatic X-ray source and an energy-resolving X-ray detector for obtaining detection signals depending on the X-ray radiation after passing through the object. A calculation unit (12) determines a k-edge 5 component of the substance from the detection signals, and a reconstruction unit (13) reconstructs a time series of k-edge image from the determined k-edge component. A flow determination unit (14) determines flow values indicative for the flow within the object from the time series of k-edge images.
    Type: Application
    Filed: November 29, 2007
    Publication date: March 11, 2010
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventor: Roland Proksa
  • Image reconstruction with voxel dependent interpolation
    Patent number: 7672424
    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.
    Type: Grant
    Filed: September 22, 2005
    Date of Patent: March 2, 2010
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Andy Ziegler, Thomas Koehler, Tim Nielsen, Roland Proksa, Dominic J. Heuscher
  • Short scan cardiac CT on a quasi axial trajectory
    Patent number: 7672423
    Abstract: A short scan uses only data from about 180° gantry rotation instead of a full 360° turn. In the provided short scan cardiac CT, a periodical axial focal spot movement is performed during gantry rotation, wherein the acquired data used for image reconstruction results from a 180° rotation of the gantry. After the data acquisition, an approximate reconstruction is performed. In a preferred embodiment the focal spot moves on a short scan saddle trajectory.
    Type: Grant
    Filed: October 11, 2006
    Date of Patent: March 2, 2010
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Roland Proksa
  • Motion artifacts compensation
    Patent number: 7672490
    Abstract: Motion is one of the most critical sources of artifacts in helical conebeam CT. By comparing opposite rays corresponding to projection data, the amount of motion may be estimated and, in the following suppression of corresponding motion artifacts may be performed according to an exemplary embodiment of the present invention. The method of motion artifact compensation may be implemented in both approximate reconstruction algorithms and exact reconstruction algorithms. Advantageously, motion during the data acquisition is detected automatically and related motion artifacts may be suppressed adaptively.
    Type: Grant
    Filed: February 4, 2005
    Date of Patent: March 2, 2010
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Thomas Kohler, Roland Proksa, Claas Bontus
  • Energy-resolved photon counting for CT
    Patent number: 7668289
    Abstract: Spectral CT systems require cheap detectors with high energy resolution. According to an aspect of the present invention, a computer tomography apparatus comprises a detector element which is segmented into a plurality of sub-pixels. Each sub-pixel has at least two thresholds and counting channels, wherein the second threshold for each sub-pixel varies over the nominal detector element. This may provide for an improved energy-resolved photon counting.
    Type: Grant
    Filed: April 25, 2006
    Date of Patent: February 23, 2010
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Roland Proksa, Michael Grass
  • METHOD AND APPARATUS FOR CORRECTING ARTIFACTS IN CIRCULAR CT SCANS
    Publication number: 20100034342
    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.
    Type: Application
    Filed: August 4, 2009
    Publication date: February 11, 2010
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventors: Peter FORTHMANN, Axel THRAN, Claas BONTUS, Roland PROKSA
  • EVENT SHARING RESTORATION FOR PHOTON COUNTING DETECTORS
    Publication number: 20100025593
    Abstract: Photon counting detectors may suffer from pulse sharing effects and fluorescence photon generation, which may lead to a degradation of the measured signals. According to an exemplary embodiment of the present invention, a detector unit is provided which is adapted for performing a coincidence detection and correction by comparing detection events of neighbouring cells, thereby providing for a coincidence identification followed by an individual coincidence correction. In order to reduce the number of coincidence detection and corresponding units per detector unit, a specific detector cell geometry may be applied.
    Type: Application
    Filed: January 28, 2008
    Publication date: February 4, 2010
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventor: Roland Proksa
  • STEREO TUBE COMPUTED TOMOGRAPHY
    Publication number: 20100002830
    Abstract: A computed tomography system includes at least two x-ray sources (108), a at least one common detector (124), and a reconstruction system (136). The at least two x-ray sources (108) are aligned at different z-axis locations at about a same angular position and concurrently emit radiation that traverses an imaging region (116). The at least one detector (124) detects radiation emitted by the at least two x-ray source (108) and generates composite data indicative of the detected radiation. The reconstruction system (136) reconstructs the composite data to generate one or more images.
    Type: Application
    Filed: July 23, 2007
    Publication date: January 7, 2010
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventors: Roland Proksa, Andy Ziegler
  • ENERGY SPECTRUM RECONSTRUCTION
    Publication number: 20090310736
    Abstract: A computed tomography system includes an x-ray source (108) that rotates about and emits radiation through an imaging region (116). At least one finite energy resolution detector (112) detects the emitted radiation. The at least one finite resolution detector (112) includes a plurality of sub-detectors (204). Each of the plurality of sub-detectors (204) is associated with one or more different energy thresholds. Each of the energy thresholds is used to count a number of incident photons based on a corresponding energy level. A reconstruction system (136) reconstructs the photon counts to generate one or more images of a subject residing within the imaging region (116).
    Type: Application
    Filed: July 2, 2007
    Publication date: December 17, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Andy Ziegler, Roland Proksa
  • IMAGING SYSTEM FOR IMAGING AN OBJECT
    Publication number: 20090266994
    Abstract: The present invention relates to an imaging system for imaging an object (20) comprising a polychromatic radiation source (2) and an energy resolving radiation detector (6). The imaging system comprises further a driving device for moving the object (20) and the radiation source (2) relatively to each other, in order to acquire truncated projections from different directions. A calculation unit determines a k-edge component at least of one of the object (20) and a substance within the object (20) from the truncated projections and determines non-truncated projections from the determined k-edge component. A reconstruction unit constructs the object using the non-truncated projections.
    Type: Application
    Filed: October 24, 2007
    Publication date: October 29, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventor: Roland Proksa
  • Imaging method with filtered back projection
    Patent number: 7596202
    Abstract: The invention relates to an imaging method, in which a projection data record of an examination area to be reconstructed is generated by acquiring projections from different projection directions, in particular with the aid of a computer tomograph. For each projection direction, a filter operator is determined that is optimally adapted to a projection geometry allocated to the respective projection direction. An image of the examination area is reconstructed from the projection data record by filtering the projections with the filter operators determined and by back projection of these filtered projections.
    Type: Grant
    Filed: December 6, 2004
    Date of Patent: September 29, 2009
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Tim Nielsen, Roland Proksa
  • RECONSTRUCTION OF AN IMAGE OF A MOVING OBJECT FROM VOLUMETRIC DATA
    Publication number: 20090232379
    Abstract: In the CT imaging of non-homogeneously moving objects such as the heart or the coronary vessel tree, there is a problem that different parts of the objects are at rest at different points in time. Thus, a gated reconstruction with a globally selected time point does not yield a sharp image of such objects. According to the present invention, a motion of the object is estimated, describing the motion of selected regions of these objects. Then, on the basis of the estimated motion, time points are determined, where these areas have minimal motion. Then, an image is reconstructed, wherein the data from which the respective regions are reconstructed, correspond to the respective time points, where the regions have minimal motion. Due to this, an improved image quality may be provided.
    Type: Application
    Filed: May 26, 2009
    Publication date: September 17, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventors: Thomas Kohler, Michael Grass, Michael Harald Kuhn, Roland Proksa
  • ADAPTIVE OVERLAPPING OF CARDIAC WEIGHTING VECTORS IN CARDIAC CT
    Publication number: 20090232372
    Abstract: A device (118) for analyzing multi-cycle cardiac computer tomography data detected by attenuating X-rays by a heart (130), comprising a first determining unit adapted to determine, based on the detected computer tomography data, a cardiac weighting function (302) for a reconstruction of an image of the heart (130), and a modifying unit adapted to modify the cardiac weighting function (302) in such a manner that an overlap of succeeding distribution functions (303) of the weighting function (302), which distribution functions (303) are assigned to different cycles of the heart (130), is at least equal to a predefined overlap threshold.
    Type: Application
    Filed: February 13, 2006
    Publication date: September 17, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Thomas Köhler, Roland Proksa
  • IMAGE RECONSTRUCTION WITH VOXEL DEPENDENT INTERPOLATION
    Publication number: 20090202036
    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.
    Type: Application
    Filed: September 22, 2005
    Publication date: August 13, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Andy Ziegler, Thomas Koehler, Tim Nielsen, Roland Proksa, Dominic J, Heuscher
  • Imaging method with back projection
    Patent number: 7570731
    Abstract: The invention relates to an imaging method, especially a computerized tomography method, with which an object is penetrated by rays from different directions and measured values, which depend upon the intensity of the rays after penetrating the object, are acquired by a detector unit. From these measured values, an object image is reconstructed by means of back projection of measured-value-dependent back projection values. Therein, the object image is divided into overlapping, quasi-spherically symmetric image segments, each being defined by an image value and a quasi-spherically symmetric base function.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: August 4, 2009
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Tim Nielsen, Andy Ziegler, Thomas Koehler, Roland Proksa
  • COMPUTED TOMOGRAPHY METHOD
    Publication number: 20090185655
    Abstract: A computed tomography method and apparatus are provided wherein a radiation source moves circularly relative to an examination zone about an axis of rotation (14). The radiation source produces a cone beam of x-rays and the focal point of this cone beam is switched between at least two positions (23a, 23b) spaced apart from each other and arranged on a line parallel to the axis of rotation to enlarge the reconstructable examination zone parallel to the axis of rotation. Preferably, the image of the examination zone is reconstructed using an iterative reconstruction method, in particular an algebraic reconstruction method or a maximum likelihood method.
    Type: Application
    Filed: September 23, 2005
    Publication date: July 23, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Peter Koken, Andy Ziegler, Michael Grass, Thomas Köhler, Roland Proksa
  • Reconstruction of an image of a moving object from volumetric data
    Patent number: 7545903
    Abstract: In the CT imaging of non-homogeneously moving objects such as the heart or the coronary vessel tree, there is a problem that different parts of the objects are at rest at different points in time. Thus, a gated reconstruction with a globally selected time point does not yield a sharp image of such objects. According to the present invention, a motion of the objects is estimated, describing the motion of selected regions of these objects. Then, on the basis of the estimated motion, time points are determined, where these areas have minimal motion. Then, an image is reconstructed, wherein the data from which the respective regions are reconstructed, correspond to the respective time points, where the regions have minimal motion. Due to this, an improved image qualify maybe provided.
    Type: Grant
    Filed: July 7, 2004
    Date of Patent: June 9, 2009
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Thomas Köhler, Michael Grass, Michael Harald Kuhn, Roland Proksa
  • IMAGING SYSTEM FOR THE GENERATION OF HIGH-QUALITY X-RAY PROJECTIONS
    Publication number: 20090080751
    Abstract: The invention relates to an imaging system and a method for generating high-quality X-ray projections (24) of a patient (1). The system comprises a rotational X-ray device (10), for example a cone-beam CT-gantry (12), and an associated data processing unit (20). During a medical intervention, low-dose raw projections (22) of the patient (1) are continuously generated from different directions. A volume of interest (23) is then reconstructed from said projections (22), from which high-quality virtual projections (24) can be calculated for a display on a monitor (25). The number and direction of said virtual projections (24) can be arbitrarily chosen by the user.
    Type: Application
    Filed: October 6, 2005
    Publication date: March 26, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS, N.V.
    Inventors: Volker Rasche, Roland Proksa
  • Automatic Adaptive Soft Tissue Thresholding for Two-Pass Ct Cone-Beam Artifact Reduction
    Publication number: 20080292157
    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.
    Type: Application
    Filed: October 6, 2006
    Publication date: November 27, 2008
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N. V.
    Inventors: Peter Forthmann, Michael Grass, Roland Proksa