376 results about "Cone beam ct" patented technology

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.

A dental prosthesis for periodontal integration is disclosed. Furthermore a customized dental prosthesis for osseointegration is disclosed having a first manufactured portion shaped to substantially conform to the three-dimensional surface of a root of a tooth to be replaced and a second manufactured portion shaped to substantially conform to the three-dimensional surface of a crown of a tooth to be replaced. Furthermore a customized manufactured splint is disclosed to position and fixate a tooth-shaped prosthesis. Furthermore a CAD/CAM based method of and a system for manufacturing a customized dental prosthesis replacing an extracted tooth is disclosed, where the extracted tooth is scanned regarding its three-dimensional shape and substantially copied using (a) an imaging system in-vitro like a 3D scanner or in-vivo like a cone beam CT system, (b) CNC machinery and (c) biocompatible material that is suitable to be integrated into the extraction socket and at least partially adopted by the existing tissue forming the socket.

A device for imaging an object, such as for breast imaging, includes a gantry frame having mounted thereon an x-ray source, a source grating, a holder or other place for the object to be imaged, a phase grating, an analyzer grating, and an x-ray detector. The device images objects by differential-phase-contrast cone-beam computed tomography. A hybrid system includes sources and detectors for both conventional and differential-phase-contrast computed tomography.

Dental prosthesis, systems, and methods of forming and using a dental prosthesis, are provided. An example of a dental prosthesis includes a first manufactured portion shaped to substantially conform to the three-dimensional surface of a root of a tooth to be replaced and a second manufactured portion shaped to substantially conform to the three-dimensional surface of a crown of the tooth. Furthermore, customized manufactured splints to position and fixate a tooth-shaped prosthesis, are provided. Furthermore, a CAD/CAM based methods of and a systems for manufacturing a customized dental prosthesis are provided. The tooth can be scanned to determine its three-dimensional shape and substantially copied using an imaging system in-vitro like a 3D scanner or in-vivo like a cone beam CT system and CNC machinery. Biocompatible material that is suitable to be integrated into the extraction socket and adopted by existing tissue forming the socket can be manufactured or engineered.

A system includes acquisition of a three-dimensional cone beam image, and determination of a dose to be delivered based on the three-dimensional image and on parameters of a treatment beam to deliver the dose. Some systems may include modification of a three-dimensional cone beam image to correct for scatter radiation, and determination of a dose based on the modified three-dimensional cone beam image.

An apparatus for cone beam computed tomography of an extremity has a digital radiation detector and a first device to move the detector along a circular detector path extending so that the detector moves both at least partially around a first extremity of the patient and between the first extremity and a second, adjacent extremity. The detector path has radius R1 sufficient to position the extremity approximately centered in the detector path. There is a radiation source with a second device to move the source along a concentric circular source path having a radius R2 greater than radius R1, radius R2 sufficiently long to allow adequate radiation exposure of the first extremity for an image capture by the detector. A first circumferential gap in the source path allows the second extremity to be positioned in the first circumferential gap during image capture.

The invention discloses a geometrical parameter calibration method of an X-ray cone beam computed tomography system and belongs to the field of the X-ray cone beam computed tomography systems (a cone beam CT for short). By means of a camera calibration technique, a geometrical position relationship among an X-ray source, a panel detector and a rotary shaft in a cone beam CT system is reproduced, thereby geometrical parameters and errors of the cone beam CT can be directly solved, the geometrical parameter calibration method is a systematized measurement solving method, the cone beam CT can beabstracted to be a basic camera system model, and then a plurality of correlative geometrical parameters in the system can be simultaneously solved. Compared with prior calibration methods, the geometrical parameter calibration method has the advantages that the geometrical parameters are not required to be measured one by one, repeated adjustment for the parameters one by one is not required, thereby the complexity level of calibration measurement of the whole system is greatly simplified, and simultaneously the stability of the cone beam CT geometrical calibration is improved.

An X-ray CT system is equipped with a gantry, couch and control cabinet and configured to scan a cone-beam X-ray toward an object along a given orbit to acquire cone-beam data in which a three-dimensional distribution of an X-ray absorption coefficient within the object is reflected. The control cabinet decides a degree of reliability for the cone-beam data according to an acquisition time of the cone-beam data, and then decides a weight for three-dimensional Radon data from the cone-beam data on the basis of the degree of reliability. Using this weight, the control cabinet reconstructs the three-dimensional Radon data based on a three-dimensional reconstruction algorithm. Thus, when the three-dimensional reconstruction algorithm for cone-beam CT is applied to medical CT, artifacts attributable to object's motion can be suppressed and temporal resolution can be improved.

The invention discloses a scattering determination and corrector method of a taper bunch CT system. After arranging a parameter, an air projected picture and a beam attenuation grid projected picture are collected. A circular scanning is carried out on the detected object. A projected picture set I of the detected object with beam attenuation grid and a projected picture set II of the detected object are collected. The projected attitude of the center of each metal ball in the beam attenuation grid is calculated. A scattered field distributing image corresponding to the projected picture of the projected picture set I is calculated through a beam attenuation grid corrector method. A projected picture set III after scattering correction is gained through the projected picture set I subtracting the corresponding scattered field distributing image. Thereby, a sequence slice image after scattering correction is reconstructed through a filter back-projection reconstruction method. The invention can be applied to the scattering correction of the taper bunch CT system from low energy to medium or high energy. The invention is a simple and effective scattering correction method of the taper bunch CT system.

The invention discloses an improved eliminating method of tapered beam CT reconstruction image annular false shade, comprising the steps as follows: the invention changes the annular false shade of reading CT reconstruction image into a straight line through a method of coordinate change, then takes a one-dimension filter parallel with the false shade as a mask to search a middle image regularly line by line and acquire sample space, at the same time calculates out the variance about the pixel value of each sample space, acknowledges the false shade according to whether the variance is less than the preset valve value, substitutes the pixel value of each sample space with the average pixel value between the point and two upper and lower false shades in the ordinate axis direction in order to eliminate the annular false shade, and finally changes the middle image free from the false shade to be under the original frame of axes to gain a corrected image.

The invention relates to a metal artifact correcting method of a cone-beam CT (computed tomography) system. The metal artifact correcting method of the cone-beam CT system comprises the steps of separating a metal projection image M (x, y) from an original orthographic projection image f(x, y), reconstructing the metal projection image M (x, y) to obtain a CT reconstruction image XMetal of the metal part, reducing the metal projection image M (x, y) of the original orthographic projection image f(x, y) to obtain a projection image fres(x, y) without the metal part, reconstructing the projection image fres(x, y) without the metal part to obtain a CT (computed tomography) image Xres without the metal part, and adding a CT (computed tomography) image Xmetal of the metal part with the CT (computed tomography) image Xres without the metal part to obtain a final CT (computed tomography) reconstruction image Xcorrection after the correction of a metal artifact. Coordinates are not changed in the metal artifact correcting method, so that the image space resolution is not lost, and the image quality is enhanced.

An X-ray source system for a CT scanner includes a plurality of X-ray sources, wherein each X-ray source of the plurality is provided with a cathode from which an electron beam is emitted, an anode to receive the electron beam and at least one grid electrode, wherein the grid electrodes are configured to selectably block radiation from said X-ray sources; a high voltage generator for applying voltage to the plurality of X-ray sources, wherein each of the plurality of X-ray sources are configured to present substantially the same load to the high voltage generator; a grid modulator configured to apply voltage to grid electrodes of each of the plurality of X-ray sources in turn; and a controller for controlling the grid modulator so that only one of the plurality of X-ray sources emits radiation at any one time.

The invention discloses a CT (Computed Tomography) value correcting method for cone-beam CT. The CT value correcting method comprises the following steps: scanning air, a water phantom and a bone tissue body phantom under different scanning conditions to respectively obtain projection data; reestablishing an image; removing noise and artifacts by adopting a polynomial fitting method based on a template image; selecting a plurality of interested regions and calculating a mean value of an attenuation coefficient and a standard deviation of the attenuation coefficient; obtaining the value range of the attenuation coefficient and taking the attenuation coefficient of maximum occurrence probability; fitting the attenuation coefficients of the air, the water phantom and the bone tissue body phantom under the different scanning conditions with corresponding ideal CT values to obtain respective fitting curves; performing CT scanning and image reestablishment on a scanned material; obtaining a CT value image according to a material attenuation coefficient image and a fitting curve and finishing the CT value correction. According to the CT value correcting method disclosed by the invention, image noise and artifact can be effectively reduced, the reestablished image of single material reaches the uniformity to the great degree, the precision of the attenuation coefficient of the material becomes higher and further high accuracy for the fitting of the curve of the CT value and the material attenuation coefficient is realized.

The utility model discloses an anti-interference correction method of flat panel detector image in cone-beam CT system, which is characterized in that collection parameter is set, the plat panel detector is shielded partially, dark image, blank exposure image and object projection image are collected; average dark field image, gain correction image and bad pixel template image are calculated; dark field correction, dark field fluctuation correction, gain correction, bad pixel correction and gain strip correction are made on the object projection image; the filtering de-noising treatment is made on the object projection image, the object segmentation image is re-constructed by the object projection image. The blank exposure image is reconstructed to be a blank segmentation image, the segmentation correction image is calculated; the segmentation correction is made on the object segmentation image; the filtering de-noising treatment is made on the object segmentation image. The utility model has the advantages that the correction result is obviously better than that of the prior correction calculation method, enabling. to effectively dispose the linear and annular artifacts that can not be eliminated by the prior correction method, moreover image signal-to-noise ratio is higher or equal to the prior level.

The invention discloses a cone-beam computed tomography image and X-ray image registration method; the method uses a regression model based on a mixing residual error convolution nerve network to build associations between two-dimension X-ray images and three dimensional cone-beam CT image non-rigid deformation parameters, and uses a mixing residual error convolution nerve network and deformation parameter iteration optimization method to realize reliable online two-dimension three dimensional image registration; the method comprises the following steps: extracting to obtain an image channel; training the regression model based on the mixing residual error convolution nerve network; carrying out two-dimension three dimensional non-rigid registration based on regression; iterating and optimizing deformation parameters; obtaining a final body image determined by the deformation parameters, and thus realizing two-dimension three dimensional image registration based on iteration regression. The method can realize reliable online two-dimension three dimensional image registration, can be applied to oral cavity clinics, and can evaluate treatments and analyze craniofacial growth according to two-dimension three dimensional image registrations.

Disclosed are embodiments of methods of and systems for detecting and biopsying lesions with a cone beam computed tomography (CBCT) system. The system comprises, in some embodiments, a CBCT device configured to output a cone beam CT image of at least a portion of a patient's breast and a multi-axis transport module, having at least three degrees of freedom and configured to position a biopsy needle within a 3D frame of reference based on inputs received from the cone beam CT device. The transport module can be configured to place the biopsy needle adjacent to, or within, a target of interest within the breast. Also disclosed are embodiments of methods of and systems for testing CBCT systems with phantoms.

The 3D CT imaging method for large view field comprises: (1) taking first single-circular orbit cone-beam CT scanning to obtain the first digital ray projection image sequence; (2) removing the platform vertical the main ray with some distance to take the second CT scanning and obtain the second image sequence; (3) correcting former two images for dark current and inconsistency; (4) recording distance from ray source to detector, former moved distance and detector level channel number; (5) with the projection rearrangement algorithm in this invention, rearranging former two images into self-contained quasi-parallel image sequence; (6) with the quasi-parallel ray reconstructing algorithm in this invention, reconstructing the 3D CT image. This invention can enlarge the view area more than 3 times with high efficiency.

The present invention is directed to a method for enabling volumetric image reconstruction from unknown projection geometry of tomographic imaging systems, including CT, cone-beam CT (CBCT), and tomosynthesis systems. The invention enables image reconstruction in cases where it was not previously possible (e.g., custom-designed trajectories on robotic C-arms, or systems using uncalibrated geometries), and more broadly offers improved image quality (e.g., improved spatial resolution and reduced streak artifact) and robustness to patient motion (e.g., inherent compensation for rigid motion) in a manner that does not alter the patient setup or imaging workflow. The method provides a means for accurately estimating the complete geometric description of each projection acquired during a scan by simulating various poses of the x-ray source and detector to determine their unique, scan-specific positions relative to the patient, which is often unknown or inexactly known (e.g., a custom-designed trajectory, or scan-to-scan variability in source and detector position).