Leland Stanford Junior University

Seetreat Pty Ltd

The University of Sydney

Opus Medical Pty Ltd

Other

Varian Medical Systems, Inc.

Asto Ct, Inc.

Paul Keall

Per Rugaard Poulsen

Doan Trang Nguyen

Ricky O'Brien

Dan Ruan

Jun Lu

Sean Pollock

Lei Xing

Rebecca Fahrig

Amit Ramakant Sawant

Dragos Constantin

Ilana Feain

Peter Horsley

Thomas Christopher Wolfgang Landgrebe

Elisabeth Weiss

Jeffrey F Williamson

Byungchul Cho

Chun-Chien Shieh

Kuldeep Makhija

Daniel Nicholas Zafir

Joubin Nasehi Tehrani

Yunzhi Ma

Walther Fledelius

Emily Brackbill

Geoffrey Hugo

Ricky O'brien

Adam Mylonas

Emily Hewson

Benjamin J Cooper

Lars Mejnertsen

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.

Kalman filter framework to estimate 3D intrafraction motion from 2D projection

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 un-shifted 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.

Dose-based optimization for multi-leaf collimator ('MLC') tracking during radiation therapy methods and apparatus

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.

Method and system for guided radiation therapy

A method of customized breathing maneuver guidance during radiotherapy treatment by configuring to a treatment couch an augmented reality system that includes a mounting assembly, a position measurement module to measure a distance from a fixed position to a patient anatomic region during a breathing cycle, and a breath monitoring and instruction screen viewable by the patient disposed proximal to the fixed position, where the patient monitors and controls a state of their breathing cycle in real time from breath state information displayed on the instruction screen, and determining the anatomic region for monitoring to measure the distance from the fixed position, determining a patient-customized breath hold amplitude by measuring a distance between a baseline exhale position a maximum inhale position, and entering breath hold amplitude data to a computer for subsequent breath hold guidance regardless of the treatment couch model setup and patient weight variations.

Method of markerless measurement and calculation for personalized and reproducible breath holds for radiation therapy and medical imaging

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.

Radiation therapy systems and methods using an external signal

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.

Method and system for in situ targeting of objects

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.

Realtime radiotherapy markerless calibration and measurement system

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.

Modulating gantry rotation speed and image acquisition in respiratory correlated (4D) cone beam CT images

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.

Method to estimate real-time rotation and translation of a target with a single x-ray imager

An inverse planning method that is capable of controlling the appearance of the implanted fiducial(s) in segmented IMRT fields for cine MV or combined MV/kV image-guided IMRT is provided. The method for radiation treatment includes computing a radiation treatment plan and delivering beams to a target in accordance with the radiation treatment plan, where computing the radiation treatment plan includes introducing a penalty in an inverse planning objective function optimization calculation to discourage or avoid blockage of one or more fiducials in optimized multi-leaf collimator (MLC) apertures.

Including fiducial markers in radiation therapy planning to facilitate real-time position monitoring during treatment delivery

A method of configuring an electron gun for generating and injecting an electron beam into a linac accelerating waveguide operating in magnetic fringe fields of an MRI scanner in the absence of a magnetic shield is provided using an appropriately programmed computer to determining an anode drift tube diameter at an injection point of a linac according to a magnetic field value from an MRI scanner and to a predetermined current density, where the magnetic field has an isocenter, determining a transverse diameter of a Type M cathode in an electron gun, according to the anode drift tube diameter and the current density, and minimizing an emittance value in an electron beam of the electron gun at an entry point of the anode drift tube by optimizing the distance between the cathode and the anode, where the electron beam is along an axis of symmetry of the magnetic field.

Method and system for operating electron guns in magnetic fields

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.

Systems and methods for segmentation of radiopaque structures in images

A method of multileaf collimator (MLC) leaf positioning in tracking-based adaptive radiotherapy is provided. The method includes determining a radiotherapy beam pattern by transforming a treatment beam plan into radiotherapy beam coordinates, determining a dose discrepancy between the radiotherapy beam pattern and a deliverable MLC aperture, where the dose discrepancy includes a sum of an overdose cost and an underdose cost to a treatment volume, and minimizing the dose discrepancy, where the dose discrepancy minimization provides a determined deliverable MLC aperture for the radiotherapy beam.

Method and system for real-time DMLC-based target tracking with optimal motion compensating leaf adaptation

A method of minimizing radiation toxicity in image guided radiotherapy (IGRT) is provided that includes using a probabilistic prediction algorithm that is operated on a suitably programmed computer and includes multimodality inputs and provides real-time geometric and topological target estimates to compensate for system latency, using an online adaptive imaging system that provides radiographic images of the target when the geometric and topological target estimates are in a region of predefined uncertainty, and using an image dose control algorithm, operating on a suitably programmed computer, that includes parameters for controlling dose per image, where instances for image acquisition are optimized according to a planned dose pattern and delivery result.

Method for reducing diagnostic radiation dose in image guided radiotherapy

A method of estimating target motion for image guided radiotherapy (IGRT) systems is provided. The method includes acquiring by a kV imaging system sequential images of a target motion, computing by the kV imaging system from the sequential images an image-based estimation of the target motion expressed in a patient coordinate system, transforming by the kV imaging system the image-based estimation in the patient coordinate system to an estimate in a projection coordinate system, reformulating by the kV imaging system the projection coordinate system in a converging iterative form to force a convergence of the projection coordinate system to output a resolved estimation of the target motion, and displaying by the kV imaging system the resolved estimation of the target motion.

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Greenwich, Australia

Paul Keall