Abstract: An iterative Kalman Filter method was developed to address the need for estimating randomly moving targets during cancer radiotherapy on a standard equipped linear accelerator. Extensive evaluation of this method using different treatment scenarios shows sub-mm accuracy and precision. In addition, the system and method allows the target (or surrogates of the target) to be monitored without the need of a learning arc, reducing additional imaging dose to the patient. In addition, the method and system performs robustly against imaging and segmentation noise.

Abstract: A method of real-time markerless measurement and calibration of a patient positioning system includes computing a three dimensional point cloud representation of a patient by using a camera to obtain depth points of the patient, where the z-direction corresponds to a direction along the focal length of the camera, demanding a z-limit that corresponds to a lower (z-min) and an upper (z-max) specification, computing a point cloud covariance and a point cloud mean for an optimized principle components analysis to compute a torso topography of the patient, determining a center point of the point cloud as an anchor measurement region and using the camera to determine a distance to the patient to establish an angle between a patient torso and a vector that is perpendicular to the camera, averaging the depth measurements in reference regions and compensating for parallax error in real-time during a calibration measurement or radiotherapy treatment plan.

Abstract: A method of real-time markerless measurement and calibration of a patient positioning system includes computing a three dimensional point cloud representation of a patient by using a camera to obtain depth points of the patient, where the z-direction corresponds to a direction along the focal length of the camera, demanding a z-limit that corresponds to a lower (z-min) and an upper (z-max) specification, computing a point cloud covariance and a point cloud mean for an optimized principle components analysis to compute a torso topography of the patient, determining a center point of the point cloud as an anchor measurement region and using the camera to determine a distance to the patient to establish an angle between a patient torso and a vector that is perpendicular to the camera, averaging the depth measurements in reference regions and compensating for parallax error in real-time during a calibration measurement or radiotherapy treatment plan.

Abstract: A method of adaptive suppression of over-smoothing in noise/artefact reduction techniques such as total variation minimization or other compressed sensing strategies for Cone Beam Computed Tomography (CBCT) images, the method including the steps of: (a) inputting a CBCT image; (b) identifying the anatomical structures of interest in the CBCT images by exploiting their likely shapes, attenuation coefficients, sizes, positions, or any other similar features that can be used to identify them from an image; (c) extracting intensity, gradient, or other image-related information of the identified anatomical structures from the CBCT image; (d) adaptively suppressing over-smoothing in noise/artefact reduction techniques such as total-variation minimization or other compressed sensing strategies at the anatomical structures of interest using the information of the anatomical structures extracted previously.

Abstract: A method of optimizing 4D cone beam computed tomography (4DCBCT) imaging is provided that includes using a scanner to generate projections of a target, where the projections are used to form a cone beam computed tomography (CBCT) scan of the target, where the CBCT includes a 3D image of the target, and using an appropriately programmed computer to control rotation speed of a gantry and projection acquisition of the CBCT in real-time according to a measured patient respiratory signal, where the real-time acquisition of the 4CBCT forms an optimized 4DCBCT image set.

Abstract: A method, and a system when implementing a method, of reducing artefacts in image creation in 4D cone beam computed tomography (4DCBCT) images, the method comprising the steps of: (a) performing a 4DCBCT scan of a target patient including a series of spaced apart projections through the target patient, with each projection having an associated estimated or measured respiratory state; (b) initially dividing the series of projections into a corresponding series of respiratory bins, with each respiratory bin having projections substantially from a portion of a cyclic respiratory state; and (c) optimising the projections at the bounds of each respiratory bin so as to improve an image quality measure of the images.

Abstract: A method of real-time estimation of target rotation and translation for 6 degrees of freedom using a single planar 2-dimensional imager and an algorithm, such as the iterative closest point (ICP) algorithm, that includes creating pairing, using a nearest neighbor algorithm, between a set of target points of at least three fiducial markers and a set of source points of the markers using K nearest neighbors, iteratively executing estimation of a rotation parameter R and a translation parameter T of the markers using a cost function such as root mean square error, terminating the estimation of R and T if the change in a mean distance between the set of target points of the markers and the set of source points of the markers is below a threshold or at a maximum iteration number, transforming the set of target points of the markers using estimated parameters, and re-associating a new set of the target points of the markers.

Abstract: A method of real-time estimation of target rotation and translation for 6 degrees of freedom using a single planar 2-dimensional imager and an algorithm, such as the iterative closest point (ICP) algorithm, that includes creating pairing, using a nearest neighbor algorithm, between a set of target points of at least three fiducial markers and a set of source points of the markers using K nearest neighbors, iteratively executing estimation of a rotation parameter R and a translation parameter T of the markers using a cost function such as root mean square error, terminating the estimation of R and T if the change in a mean distance between the set of target points of the markers and the set of source points of the markers is below a threshold or at a maximum iteration number, transforming the set of target points of the markers using estimated parameters, and re-associating a new set of the target points of the markers.

Abstract: A method of optimizing 4D cone beam computed tomography (4DCBCT) imaging is provided that includes using a scanner to generate projections of a target, where the projections are used to form a cone beam computed tomography (CBCT) scan of the target, where the CBCT includes a 3D image of the target, and using an appropriately programmed computer to control rotation speed of a gantry and projection acquisition of the CBCT in real-time according to a measured patient respiratory signal, where the real-time acquisition of the CBCT forms an optimized 4DCBCT image set.