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: Systems, methods, and apparatus are disclosed for cardiac structure tracking. An example method includes segmenting a diaphragm or respiratory surrogate, heart, and target. The method also includes performing a peak-exhale to peak-inhale registration and generating a respiratory motion model. The method further includes tracking the diaphragm using X-ray imaging and estimating a target position for an x-ray guided cardiac radioablation treatment. The example method provides directly, precisely controlled x-ray guided cardiac radioablation that accurately targets the substrates of cardiac ablation while minimizing doses to healthy tissue.

Abstract: Methods, apparatuses and systems are disclosed for dose-based optimization related to multi-leaf collimator (“MLC”) tracking during radiation therapy. In an example, a method includes calculating a planned radiation dose using an MLC plan in an unshifted dose volume, acquiring, using a radiation machine, a target position through motion tracking, and shifting the dose volume by the target position. The method also includes integrating a three-dimensional dose into a two-dimensional beam’s eye view grid and fitting, using the radiation machine for each leaf track, an MLC aperture by minimizing a cost function. The method further includes calculating and accumulating a delivered dose based on the fitted leaf positions of the MLC and updating a gantry position and MLC leaves to update a next planned dose.

Abstract: There is disclosed a method for estimating the position of a target in a body of a subject. The method includes, receiving an external signal that is related with motion of the target; and using a model of a correlation between the external signal and the motion of the target to estimate the position of the target, wherein said position estimation includes an estimate of three dimensional location and orientation of the target. The method further includes periodically receiving a 2-dimensional projection of the target; and updating the model of correlation between the external signal and the motion of the target based on a comparison of the estimated position of the target and the 2-dimensional projection of the target. The method is used in guided radiation therapy.

Abstract: A method for tracking a target located within a body, whilst scanning the body using X-ray projections, the method including the steps of: (a) providing a first prior image of the body and target indicating their relative position; (b) iteratively performing, for a series of time intervals, the steps of: (i) acquiring a few spatially distributed x-ray projections of the target area; (ii) determining one of a series of motion phases for each x-ray projection; (iii) performing an iterative reconstruction of the image for each of the motion phases; and (iv) outputting a resultant image for a current time interval.

Abstract: The present invention is concerned with a method and system for guiding a radiation therapy system. The method comprises: capturing an image of a target area to which radiation is to be delivered; analysing the image with a trained convolutional neural network to determine the position of one or more objects of interest present in the target area; and outputting the determined position/s to the radiation therapy system.

Abstract: There is disclosed a method for estimating the position of a target in a body of a subject. The method includes, receiving an external signal that is related with motion of the target; and using a model of a correlation between the external signal and the motion of the target to estimate the position of the target, wherein said position estimation includes an estimate of three dimensional location and orientation of the target. The method further includes periodically receiving a 2-dimensional projection of the target; and updating the model of correlation between the external signal and the motion of the target based on a comparison of the estimated position of the target and the 2-dimensional projection of the target. The method is used in guided radiation therapy.

Abstract: A method for tracking a target located within a body, whilst scanning the body using X-ray projections, the method including the steps of: (a) providing a first prior image of the body and target indicating their relative position; (b) iteratively performing, for a series of time intervals, the steps of: (i) acquiring a few spatially distributed x-ray projections of the target area; (ii) determining one of a series of motion phases for each x-ray projection; (iii) performing an iterative reconstruction of the image for each of the motion phases; and (iv) outputting a resultant image for a current time interval.

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, 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 determining a model of a marker includes obtaining projection images, each of the projection images having an image of a marker that indicates a shape of the marker, determining binary images of the marker for respective ones of the projection images, and constructing a three-dimensional model of the marker using the binary images, the three-dimensional model comprising a set of voxels in a three-dimensional space that collectively indicates a three-dimensional shape of the marker, wherein the act of constructing the three-dimensional model is performed using a processing unit.

Abstract: A method of determining a model of a marker includes obtaining projection images, each of the projection images having an image of a marker that indicates a shape of the marker, determining binary images of the marker for respective ones of the projection images, and constructing a three-dimensional model of the marker using the binary images, the three-dimensional model comprising a set of voxels in a three-dimensional space that collectively indicates a three-dimensional shape of the marker, wherein the act of constructing the three-dimensional model is performed using a processing unit.

Abstract: An improved method and apparatus for respiratory audio-visual biofeedback are disclosed. A guide patterned after a breathing cycle comfortable to the patient serves as a target. The target is displayed as a bar moving vertically upward during inhale and vertically downward during exhale, between fixed end ex-hale and end in-hale limits. The patient's current respiratory position is also displayed as a bar, oriented parallel to the target bar so that the difference between the current position and the target position is easy for the patient to see.

Abstract: Motion artifacts and patient dose during 4D CT imaging are reduced by adaptive control of data acquisition. The respiration signal (310) and CT data acquisition (340) are linked, such that ‘bad’ data from erratic breathing cycles that cause artifacts is not acquired by pausing CT data acquisition (360) when erratic breathing is detected, and not resuming CT data acquisition until steady-state respiration is resumed. Training data is used to develop a tolerance envelope for a respiratory signal such that for erratic breathing cycles the respiratory signal is not within the tolerance envelope (330).

Abstract: An improved method and apparatus for respiratory audio-visual biofeedback are disclosed. A guide patterned after a breathing cycle comfortable to the patient serves as a target. The target is displayed as a bar moving vertically upward during inhale and vertically downward during exhale, between fixed end ex-hale and end in-hale limits. The patient's current respiratory position is also displayed as a bar, oriented parallel to the target bar so that the difference between the current position and the target position is easy for the patient to see.

Abstract: Computed axial tomography images of different respiratory phases of lungs are obtained, where the intensity of the image measures lung density. One image is deformed to the coordinate space of the other image, and the differences between the intensity values of the other image as compared to the mapped image are evaluated as measures of ventilation.