Abstract: The present invention is directed to a method of multi-motion compensation for high-quality cone-beam CT of the head. A multi-stage approach is incorporated that includes a pre-conditioning stage in which an initial estimation of the motion trajectory is obtained with 3D-2D registration using the motion-contaminated CBCT and projection data. In the present invention, the motion-contaminated CBCT is used as a basis for 3D-2D registration in the pre-conditioning stage to capture large amplitude, rapid movements of the head and provide better initialization of the autofocus solution.

Abstract: Techniques for computed tomography (CT) image reconstruction are presented. The techniques can include acquiring, by a detector grid of a computed tomography system, detector signals for a location within an object of interest representing a voxel, where each detector signal of a plurality of the detector signals is obtained from an x-ray passing through the location at a different viewing angle; reconstructing a three-dimensional representation of at least the object of interest, the three-dimensional representation comprising the voxel, where the reconstructing comprises computationally perturbing a location of each detector signal of the plurality of detector signals within the detector grid, where the computationally perturbing corresponds to randomly perturbing a location of the x-ray within the voxel; and outputting the three-dimensional representation.

Abstract: A system and method for metal artifact avoidance in 3D x-ray imaging is provided. The method includes determining a 3D location of metal in an object or volume of interest to be scanned; estimating a source-detector orbit that will reduce the severity of metal artifacts; moving an imaging system to locations consistent with the source-detector orbit that was estimated; and scanning the object according to the source-detector orbit.

Abstract: An integrated computed tomography (CT) treatment couch system may include a base platform configured to couple to a rotatable floor component associated with a medical accelerator, a pedestal component mounted to the base platform, a treatment couchtop disposed on the pedestal component, and a CT scanner device. The CT scanner device may include a support structure and a CT gantry. The support structure may be mounted to the base platform or to the pedestal component. The CT gantry may have a bore and may be oriented such that the bore is in line with the treatment couchtop. The CT gantry may be configured to generate on-line helical CT scans to guide radiotherapy provided by the medical accelerator.

Abstract: A method and system is disclosed for analyzing and evaluating image data of a subject. The image data can be collected with an imaging system in a selected manner and/or motion. More than one projection may be combined to generate and create a selected view of the subject. The evaluation may be a location determination of a member positioned within the subject.

Abstract: An electromagnetic tracking system including a patient support element and an electromagnetic field generator. The patient support element is superposed relative to the electromagnetic field generator, and the electromagnetic field generator is selectively moveable relative to the patient support element.

Abstract: A device receives a prior image associated with an anatomy of interest, and receives measurements associated with the anatomy of interest. The device processes the prior image and the measurements, with a reconstruction of difference technique, to generate a difference image associated with the anatomy of interest, wherein the difference image indicates one or more differences between the prior image and the measurements. The device generates, based on the difference image and the prior image, a final image associated with the anatomy of interest, and provides, for display, the final image associated with the anatomy of interest.

Abstract: The present invention is directed to a system and method for dual-energy (DE) or multiple-energy (spectral) cone-beam computed tomography (CBCT) using a configuration of multiple x-ray sources and a single detector. The x-ray sources are operated to produce x-ray spectra of different energies (peak kilovoltage (kVp) and/or filtration). Volumetric 3D image reconstruction and dual or triple energy 3D image decomposition can be executed using data from the CBCT scan. The invention allows for a variety of selections in energy and filtration associated with each source and the order of pulsing for each source (“firing pattern”). The motivation for distributing the sources along the z direction in CBCT includes extension of the longitudinal field of view and reduction of cone-beam artifacts.

Abstract: The present invention is directed to an alternative geometric calibration method based on a calibration phantom with multiple line-shaped markers. The markers can in some embodiments take the form of radio-opaque wires. Line fiducials overcome the occlusion hazards of spherical fiducials, because their projections overlap very mildly as long as the wires are mutually non-coplanar in 3D. This makes the phantom amenable to a wider range of orbits and less sensitive to phantom positioning. Equations relating the pose of 3D line-shaped objects to their 2D radiographic projections are then used as the basis for view-by-view geometry estimation. The technique can flexibly accommodate a wide range of different CT scan trajectories, including strongly noncircular trajectories known to provide better image quality than standard circular scans.

Abstract: An electromagnetic tracking system including a patient support element and an electromagnetic field generator. The patient support element is superposed relative to the electromagnetic field generator, and the electromagnetic field generator is selectively moveable relative to the patient support element.

Abstract: An embodiment in accordance with the present invention provides a method for 3D-2D registration (for example, registration of a 3D CT image to a 2D radiograph) that permits deformable motion between structures defined in the 3D image based on a series of locally rigid transformations. This invention utilizes predefined annotations in 3D images (e.g., the location of anatomical features of interest) to perform multiple locally rigid registrations that yield improved accuracy in aligning structures that have undergone deformation between the acquisition of the 3D and 2D images (e.g., a preoperative CT compared to an intraoperative radiograph). The 3D image is divided into subregions that are masked according to the annotations, and the registration is computed simultaneously for each divided region by incorporating a volumetric masking method within the 3D-2D registration process.

Abstract: 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.

Abstract: Selected artifacts, which may be based on distortions or selected attenuation features, may be reduced or removed from a reconstructed image. Various artifacts may occur due to the presence of a metal object in a field of view. The metal object may be identified and removed from a data that is used to generate a reconstruction.

Abstract: A tracking and navigation system is provided. The system includes an imaging or treatment device, a tracker device, and a fiducial marker. At least part of the imaging or treatment device is movable relative to a patient. The tracker device is mounted on the imaging or treatment device and is movable therewith relative to the patient. The fiducial marker may be fixed relative to the patient to define a patient coordinate system. The fiducial marker is detectable by the tracker device to substantially maintain registration between the tracker device and the patient coordinate system. A tracking and navigation kit including the tracker device and at least one fiducial marker may also be provided, for example, for retrofitting to existing imaging or treatment devices.

Abstract: An apparatus for cone beam computed tomography can include a support structure, a scanner assembly coupled to the support structure for controlled movement in at least x, y and z orientations, the scanner assembly can include a DR detector configured to move along at least a portion of a detector path that extends at least partially around a scan volume with a distance D1 that is sufficiently long to allow the scan volume to be positioned within the detector path; a radiation source configured to move along at least a portion of a source path outside the detector path, the source path having a distance D2 greater than the distance D1, the distance D2 being sufficiently long to allow adequate radiation exposure of the scan volume for an image capture by the detector; and a first gap in the detector path.

Abstract: An embodiment in accordance with the present invention provides a technique for localizing structures of interest in projection images (e.g., x-ray projection radiographs or fluoroscopy) based on structures defined in a preoperative 3D image (e.g., MR or CT). Applications include, but are not limited to, spinal interventions. The present invention achieves 3D-2D image registration (and particularly allowing use with a preoperative MR image) by segmenting the structures of interest in the preoperative 3D image and generating a simulated projection of the segmented structures to be aligned with the 2D projection image. Other applications include various clinical scenarios involving 3D-2D image registration, such as image-guided cranial neurosurgery, orthopedic surgery, biopsy, and radiation therapy.

Abstract: A system for cone beam computed tomography of an extremity has an x-ray source and a digital radiographic detector both revolved about a central imaging axis so that the detector moves at least partially around a first extremity of a patient and, if the extremity is the leg of the patient, the detector moves between the legs of the patient. The detector path has a radial distance less than that of the source path. A housing that encloses the source and detector includes a pivoting door to allow sideways access for the patient's leg to be placed at the central imaging axis.

Abstract: An embodiment in accordance with the present invention provides a method for 3D-2D registration (for example, registration of a 3D CT image to a 2D radiograph) that permits deformable motion between structures defined in the 3D image based on a series of locally rigid transformations. This invention utilizes predefined annotations in 3D images (e.g., the location of anatomical features of interest) to perform multiple locally rigid registrations that yield improved accuracy in aligning structures that have undergone deformation between the acquisition of the 3D and 2D images (e.g., a preoperative CT compared to an intraoperative radiograph). The 3D image is divided into subregions that are masked according to the annotations, and the registration is computed simultaneously for each divided region by incorporating a volumetric masking method within the 3D-2D registration process.

Abstract: A system for cone beam computed tomography of an extremity has an x-ray source and a digital radiographic detector both revolved about a central imaging axis so that the detector moves at least partially around a first extremity of a patient and, if the extremity is the leg of the patient, the detector moves between the legs of the patient. The detector path has a radial distance less than that of the source path. A housing that encloses the source and detector includes a pivoting door to allow sideways access for the patient's leg to be placed at the central imaging axis.

Abstract: A novel method for simulating radiation dose reduction that enables previews of low-dose x-ray projection images, low-dose computed tomography images and/or cone-beam CT images. Given an existing projection or set of projections of the patient acquired at a nominal dose, the method provides a means to produce highly accurate preview images that accurately reflect the image quality associated with reduced radiation dose. The low-dose preview image accounts for characteristics of the imaging system, including blur, variations in detector gain and electronic noise, and does so in a manner that yields accurate depiction of the magnitude and correlation of image noise in the preview images. A calibration step may be included to establish the system-specific relationship between the mean and variance in detector signal, and incorporate an accurate model for system blur such that correlations in the resulting LDP images are accurate.