Abstract: An x-ray imaging apparatus and associated methods are provided to process projection data from an offset detector during a helical scan, including view completion. The detector may be offset in the channel and/or axial direction. Projection data measured from a current view is combined with projection data measured from at least one conjugate view to reconstruct a target image. A two-dimensional aperture weighting scheme is used to address data redundancy.

Abstract: An imaging apparatus and associated methods are provided to receive measured projection data in a primary region and correct for scatter by processing the imaging data as two separate components: non-scatter-corrected data and scatter-only data. Separate image processing (e.g., reconstruction) allows for the use of individualized data processing, including filters, suited to the source data, thereby focusing on specific aspects of the source data, including, for example, noise and artifact reduction, resolution, edge preservation, etc. Combining the separately processed data results in an optimized balance of these aspects with improved image quality.

Abstract: An x-ray imaging apparatus and associated methods are provided to receive measured projection data in a primary region and measured scatter data in a shadow region and determine an estimated scatter in the primary region during a current rotation based on the measured scatter data in the shadow region from a neighboring rotation. Coverage of the shadow region during the neighboring rotation overlaps the primary region during the current rotation. A beamformer is configured to adjust a shape of the radiation beam to create the primary and shadow regions on the detector, including an embodiment to follow the Tam-Danielson window during a helical scan.

Abstract: Multimodal imaging apparatus and methods include a rotatable gantry system with multiple sources of radiation comprising different energy levels (for example, kV and MV). Fast slip-ring technology and helical scans allow data from multiple sources of radiation to be combined or utilized to generate improved images and workflows, including for IGRT. Features include increasing the precision of spatial registrations between respective image sets to allow more precise radiation treatment delivery, reducing image artifacts (e.g., scatter, metal and beam hardening, image blur, motion, etc.), and utilization of dual energy imaging (e.g., for material separation and quantitative imaging, patient setup, online adaptive IGRT, etc.).

Abstract: An imaging apparatus and associated methods are provided to receive measured projection data in a primary region and correct for scatter by processing the imaging data as two separate components: non-scatter-corrected data and scatter-only data. Separate image processing (e.g., reconstruction) allows for the use of individualized data processing, including filters, suited to the source data, thereby focusing on specific aspects of the source data, including, for example, noise and artifact reduction, resolution, edge preservation, etc. Combining the separately processed data results in an optimized balance of these aspects with improved image quality.

Abstract: An x-ray imaging apparatus and associated methods are provided to process projection data from an offset detector during a helical scan, including view completion. The detector may be offset in the channel and/or axial direction. Projection data measured from a current view is combined with projection data measured from at least one conjugate view to reconstruct a target image. A two-dimensional aperture weighting scheme is used to address data redundancy.

Abstract: An x-ray imaging apparatus and associated methods are provided to receive measured projection data in a primary region and measured scatter data in a shadow region and determine an estimated scatter in the primary region during a current rotation based on the measured scatter data in the shadow region from a neighboring rotation. Coverage of the shadow region during the neighboring rotation overlaps the primary region during the current rotation. A beamformer is configured to adjust a shape of the radiation beam to create the primary and shadow regions on the detector, including an embodiment to follow the Tam-Danielson window during a helical scan.

Abstract: A computed tomography (CT) system and method is provided. The CT system is used to carry out an image improvement method in which a prior or previously-acquired patient image can be used to supplement or otherwise improve an acquired CT image, wherein the acquired projection data representative of the acquired CT image might be truncated or otherwise incomplete/insufficient to accurately and stably recover the scanned object/patient.

Abstract: A radiotherapy delivery device is provided. The device includes a source of therapeutic radiation and a first detector positioned to receive radiation from the source of therapeutic radiation. The device also includes a source of imaging radiation and a second detector positioned to receive radiation from the source of imaging radiation. A collimator assembly is positioned relative to the second source of radiation to selectively control a shape of a radiation beam emitted by the second radiation source to selectively expose part or the whole of the second radiation detector. A reconstruction processor can be operatively coupled to the detector and configured to generate patient images based on radiation received by the second detector from the second source of radiation. The device is configured to move from one imaging geometry to another using all or part of the second detector.

Abstract: An x-ray imaging apparatus and associated methods are provided to receive measured projection data from a wide aperture scan of a wide axial region and a narrow aperture scan of a narrow axial region within the wide axial region and determine an estimated scatter in the wide axial region using an optimized scatter estimation technique. The optimized scatter estimation technique is based on the difference between the measured scatter in the narrow axial region and the estimated scatter in the narrow axial region. Kernel-based scatter estimation/correction techniques can be fitted to minimize the scatter difference in the narrow axial region and thereafter applying the fitted (optimized) kernel-based scatter estimation/correction to the wide axial region. Optimizations can occur in the projection data domain or the reconstruction domain. Iterative processes are also utilized.

Abstract: An imaging apparatus and associated methods are provided to efficiently estimate scatter during multi-fraction treatments for improved quality and workflow. Estimated scatter from one fraction during a treatment course can be utilized during subsequent fractions, allowing for measurements with higher scatter-to-primary ratios. The quality of scatter estimates can be maintained, while workflow improves and dosage decreases. Scan configuration limits can be utilized to maintain a minimum level of scatter measurement quality. Patient information can be monitored to ensure that prior fraction scatter estimates are still applicable to current patient status.

Abstract: Multimodal imaging apparatus and methods include a rotatable gantry system with multiple sources of radiation comprising different energy levels (for example, kV and MV). Fast slip-ring technology and helical scans allow data from multiple sources of radiation to be combined or utilized to generate improved images and workflows, including for IGRT. Features include large field-of-view (LFOV) MV imaging, kV region-of-interest (ROI) imaging, and scalable field-of-view (SFOV) dual energy imaging.

Abstract: A method of scanning parameter optimization, which method may be useful with image-guided radiation therapy (IGRT), allows for controlling exposure of a beam from an x-ray source and/or controlling the detection mechanism for an x-ray detector of imaging radiation of a radiation-delivery device based on one or more parameters of a region of interest of a patient. The one or more parameters of the region of interest may include a dimension, outer contour, density, location relative to an outlet of the beam, location relative to isocenter, location to the whole patient body, etc. Exposure of the patient to the beam may be varied via modulation of one or more scanning parameters for controlling an aspect of the beam and/or the detector to provide for targeted and or reduced radiation exposure of the patient or portion of the patient, and/or for improved quality of guiding images. The modulation may be varied depending on a view angle of the region of interest from a portion of the radiation-delivery device.

Abstract: An x-ray imaging apparatus and associated methods are provided to receive measured projection data in a primary region and measured scatter data in asymmetrical shadow regions and determine an estimated scatter in the primary region based on the measured scatter data in the shadow region(s). The asymmetric shadow regions can be controlled by adjusting the position of the beam aperture center on the readout area of the detector. Penumbra data may also be used to estimate scatter in the primary region.

Abstract: An x-ray imaging apparatus and associated methods are provided to execute multi-pass imaging scans for improved quality and workflow. An imaging scan can be segmented into multiple passes that are faster than the full imaging scan. Data received by an initial scan pass can be utilized early in the workflow and of sufficient quality for treatment setup, including while the another scan pass is executed to generate data needed for higher quality images, which may be needed for treatment planning. In one embodiment, a data acquisition and reconstruction technique is used when the detector is offset in the channel and/or axial direction for a large FOV during multiple passes.

Abstract: Multimodal imaging apparatus and methods include a rotatable gantry system with multiple sources of radiation comprising different energy levels (for example, kV and MV). Fast slip-ring technology and helical scans allow data from multiple sources of radiation to be combined or utilized to generate improved images and workflows, including for IGRT. Features include increasing the precision of spatial registrations between respective image sets to allow more precise radiation treatment delivery, reducing image artifacts (e.g., scatter, metal and beam hardening, image blur, motion, etc.), and utilization of dual energy imaging (e.g., for material separation and quantitative imaging, patient setup, online adaptive IGRT, etc.).

Abstract: A photon-counting system includes photon-counting detectors that output photon-counting signals to indicate a number of photons impinging on the photon-counting detectors. The system also includes analog-to-digital conversion circuits, which convert one of the photon-counting signals into a digital photon-counting signals, and a processor that processes the digital photon-counting signals to extract information from the photon-counting signals. The information extracted can include a photon-counting rate. An intelligent multiplexer that, based on the photon-counting rate, modifies interconnection of the photon-counting detectors and analog-to-digital conversion circuits and provides digital photon-counting signals for a selected set of the analog-to-digital converters to the processor.

Abstract: A PET/CT imaging system is provided. The imaging system includes a PET detection system having a plurality of detector rings and an axial gap between at least two adjacent detector rings within the plurality of detector rings. The imaging system includes a CT system having an x-ray generator and a CT detection system positioned within the axial gap between the at least two detector rings. The system is configured to collect PET data and CT data on the same volume of interest substantially simultaneously.

Abstract: A hybrid imaging system includes a magnetic resonance scanner and a second modality imaging system disposed in the same radio frequency isolation space. The second modality imaging system includes radiation detectors configured to detect at least one of high energy particles and high energy photons. In some embodiments a retractable radio frequency screen is selectively extendible into a gap between the magnetic resonance scanner and the second modality imaging system. In some embodiments shim coils are disposed with the magnetic resonance scanner and are configured to compensate for distortion of the static magnetic field of the magnetic resonance scanner produced by proximity of the second modality imaging system.

Abstract: A PET/CT imaging system is provided. The imaging system includes a PET detection system having a plurality of detector rings and an axial gap between at least two adjacent detector rings within the plurality of detector rings. The imaging system includes a CT system having an x-ray generator and a CT detection system positioned within the axial gap between the at least two detector rings. The system is configured to collect PET data and CT data on the same volume of interest substantially simultaneously.