摘要:
A method for reconstructing an image of an object utilizing a cone-beam volumetric computed tomographic imaging apparatus includes helically scanning the object with a radiation source utilizing the cone-beam volumetric computed tomographic imaging apparatus, selecting radiation beams emitted by the radiation source passing through a pixel P, a Tam-window, and a Katsevich window, filtering the selected projection data, and reconstructing an image of the object utilizing the filtered selected projection data including projection data within the Katsevich window and outside the Tam-window.
摘要:
A method of improving a resolution of an image using image reconstruction is provided. The method includes acquiring scan data of an object and forward projecting a current image estimate of the scan data to generate calculated projection data. The method also includes applying a data-fit term and a regularization term to the scan data and the calculated projection data and modifying at least one of the data fit term and the regularization term to accommodate spatio-temporal information to form a reconstructed image from the scan data and the calculated projection data.
摘要:
A method for facilitating a reduction in image artifacts is provided. The method includes receiving data regarding a scan of an object, reconstructing a plurality of images using the received data to form a three-dimensional image space, determining an orientation for a maximum intensity pixel operation, locating the maximum intensity pixels within a plurality of ray paths in accordance with the determined orientation, and filtering around each maximum intensity pixel along each ray path.
摘要:
Systems, methods and apparatus are provided through which in one aspect, a three-dimensional (3D) image of an object is constructed from a plurality of two-dimensional (2D) images of the object using a specialized filter. In some embodiments, the specialized filter implements a linear ramp function, a windowing function, and/or a polynomial function. In some embodiments, the 3D image is back-projected from the filtered two-dimensional images, yielding a 3D image that has improved visual distinction of overlapping anatomic structures and reduced blurring.
摘要:
Methods and apparatus for an imaging system are provided. The imaging system includes a gantry having a stationary member coupled to a rotating member. The rotating member has an opened area proximate an axis about which the rotating member rotates. An x-ray source provided on the rotating member. An x-ray detector may be disposed on the rotating member and configured to receive x-rays from the x-ray source. A rotary transformer having circumferentially disposed primary and secondary windings may form part of a contactless power transfer system that rotates the rotatable portion of the gantry at very high speeds, the primary winding being disposed on the stationary member and the secondary winding being disposed on the rotating member.
摘要:
The present invention is directed to a method and system of controlling rotation of a gantry to rotate at a rotational speed such that a desired relationship between center projection angles of neighboring partial scans is maintained.
摘要:
A method and apparatus for tailoring the profile of an x-ray beam for radiographic imaging for a specific subject is disclosed. The invention includes a filter assembly having a pair of filters, each of which may be dynamically controlled by a motor assembly during data acquisition. The filters are positionable in the x-ray beam so as to shape the intensity profile of the x-ray beam. In one exemplary embodiment, the filters are dynamically positioned during CT data acquisition based on the shape of the subject. A method of determining the shape of the subject prior to CT data acquisition is also disclosed.
摘要:
A CT imaging system has a rotatable gantry, a table movable fore and aft through an opening defined within the rotatable gantry, and a controller that incrementally moves a subject disposed on the table through a number of discrete data acquisition positions for the acquisition of physiologically gated CT data. The controller also coordinates acquisition of imaging data from the subject at a first data acquisition position within a physiological cycle of the subject and only advances the subject to a next data acquisition position if the imaging data acquired at the first data acquisition position is deemed acceptable. The controller also detects irregularities and physiological motion of the subject and responsive thereto, suspends data acquisition until the irregularity passes, such as, suspending data acquisition until a next cardiac cycle if a heart arrhythmia is detected.
摘要:
A method for calculating an element of a projection includes calculating an element Ai,j of a projection matrix using at least two different rays through a voxel.
摘要:
A method for compensating for table sag is described. The method includes receiving a first dimension of a table, scanning a patient placed on the table to obtain a first data set, generating an image of the table by performing the scanning with the patient on the table, and determining a difference between the first dimension and a second dimension of the table in the image.