Accuray Inc.

Amit Jain

Daniel Gagnon

Zhicong Yu

Chuanyong Bai

Jacob D Shea

Calvin R Maurer

Wenli Wang

Georgios Prekas

Robert Zahn

Marc Chappo

Jr Calvin R Maurer

Saturation in at least one saturated ray is in a method including identifying a saturated ray corresponding to a first ray of a radiation source received at a radiation detector after passing through a reference point during a current view of the radiation detector, identifying at least one non-saturated ray corresponding to a second ray of the radiation source received at the radiation detector, and responsive to the identifying, adjusting a value for the saturated ray based on a value of the at least one non-saturated ray. The non-saturated ray can be a ray from an adjacent view of a current rotation, an adjacent view of a previous or subsequent rotation, or a conjugate ray. Methods of selecting a gain level to avoid saturation are also disclosed.

Methods for saturation correction and dynamic gain configuration and apparatuses for performing the same

Disclosed herein is an imaging system including a first x-ray source configured to produce first x-ray photons in a first energy range suitable for imaging, project the first x-ray photons onto an area designated for imaging, a rotatable gantry configured to rotate the first x-ray source such that the first x-ray source traverses an angular path, and a data processor having an analytical portion. The analytical portion is configured to collect first data relating to the transmission of the first x-ray photons through the area designated for imaging at a set of image-collection angles along the angular path, collect background data at a set of background-collection angles along the angular path, wherein the system acquires more than one image of the designated area for imaging between background angles. The analytical portion is also configured to remove errors in the first data using the background data, and generate a corrected image based on the removal of errors in the first data.

Sparse background measurement and correction for improving imaging

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.

Optimized scanning methods and tomography system using region of interest data

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.

Asymmetric scatter fitting for optimal panel readout in cone-beam computed tomography

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.

Method and apparatus for improving scatter estimation and correction in imaging

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.

Method and apparatus for image reconstruction and correction using inter-fractional information

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.

Noise and artifact reduction for image scatter correction

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.

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Solon, OH, United States of America

Amit Jain