Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A deliverable four dimensional (4D) intensity modulated radiation therapy (IMRT) planning method is disclosed, for delivery using a linear accelerator with a dynamic multi-leaf collimator (DMLC). A 4D computed tomography (CT) scan is used for segmenting tumor anatomy on a reference phase of periodic motion of the tumor. Deformable registration of the 4D CT data is used to generate corresponding anatomical structures on other phases. Preferably, the collimator for each beam position is aligned using the gross tumor volume (GTV) centroid motion corresponding to the periodic motion of the tumor, as determined from the two dimensional (2D) projection of a given beam position. A deliverable IMRT plan is created on the 4D CT image set in which the MLC leaf positions and beam on/off status can vary as a function of respiratory phase by solving a four dimensional optimization problem. The mechanical constraints of the MLC leaves are included in the optimization.

Abstract: A displacement and velocity based prospective cine CT (PDV CT) method is disclosed for starting image acquisition if the displacement and velocity are simultaneously within predetermined tolerances, thus essentially sorting 2D CT images in a five dimensional parameter space, where displacement and the sign of the velocity are used for the temporal sorting, replacing the use of either phase or displacement as the temporal parameter during retrospective sorting, with velocity as a separate parameter correlating to some parameter of the system, e.g. the airflow rate, making it possible to do the image sorting in real-time.

Abstract: A method of profiling respiratory motion is provided that includes estimating a temporal respiratory pattern, using a warping function to map the temporal respiratory pattern to a corresponding phase value, using a baseline drift function to determine drift in the temporal respiratory pattern, and noise filtering the temporal respiratory pattern, where variations in a respiratory motion are provided. The warping function includes combining an elliptical shape prior for providing iso-phase events in real-time, where the elliptical shape prior is in an augmented state space and Poincare´ sectioned. Parameters of the ellipse are estimated, where a projection of a center of the ellipse onto an observed respiratory position provides a real-time estimation for baseline drift of the respiratory motion.

Abstract: A deliverable four dimensional (4D) intensity modulated radiation therapy (IMRT) planning method is disclosed, for delivery using a linear accelerator with a dynamic multi-leaf collimator (DMLC). A 4D computed tomography (CT) scan is used for segmenting tumor anatomy on a reference phase of periodic motion of the tumor. Deformable registration of the 4D CT data is used to generate corresponding anatomical structures on other phases. Preferably, the collimator for each beam position is aligned using the gross tumor volume (GTV) centroid motion corresponding to the periodic motion of the tumor, as determined from the two dimensional (2D) projection of a given beam position. A deliverable IMRT plan is created on the 4D CT image set in which the MLC leaf positions and beam on/off status can vary as a function of respiratory phase by solving a four dimensional optimization problem. The mechanical constraints of the MLC leaves are included in the optimization.

Abstract: The present invention provides a radiotherapy treatment apparatus that includes a treatment beam, a magnetic field disposed parallel collinear to the treatment beam, and a target that is disposed along the treatment beam. The treatment beam can be a charged particle beam, a proton beam, an electron beam, or a linear accelerator (Linac) beam. The magnetic field is from a magnetic resonance imager (MRI), a megavolt x-ray imager, or a kilovolt x-ray imager and is disposed to operate in coordination with operation of the treatment beam and to narrow the beam. The tumor is disposed to rotate with respect to the treatment beam and the magnetic field, or the treatment beam and the magnetic field are disposed to rotate up to 360° with respect to the target when mounted to a ring gantry. The apparatus can include a rotation angle dependent shim disposed to account for Earth's magnetic field.

Abstract: The present invention provides a method for estimation of retrospective and real-time 3D target position by a single imager. The invention includes imaging a target on at least one 2D plane to determine 2D position and/or position components of the target, and resolving a position and/or position component along at least one imager axis of the target using a spatial probability density. The present invention provides a probability-based method for accurate estimation of the mean position, motion magnitude, motion correlation, and trajectory of a tumor from CBCT projections. The applicability of the method for tumors with periodic respiratory motion and for prostate are provided. Clinical feasibility is demonstrated for a pancreas tumor. The method includes monoscopic tracking of the 3D prostate position utilizing the spatial probability density to estimate the unresolved motion from the resolved motion. The method is applicable to prostate tracking even with a population-based probability density.

Abstract: A displacement and velocity based prospective cine CT (PDV CT) method is disclosed for starting image acquisition if the displacement and velocity are simultaneously within predetermined tolerances, thus essentially sorting 2D CT images in a five dimensional parameter space, where displacement and the sign of the velocity are used for the temporal sorting, replacing the use of either phase or displacement as the temporal parameter during retrospective sorting, with velocity as a separate parameter correlating to some parameter of the system, e.g. the airflow rate, making it possible to do the image sorting in real-time.

Abstract: A deliverable four dimensional (4D) intensity modulated radiation therapy (IMRT) planning method is disclosed, for delivery using a linear accelerator with a dynamic multi-leaf collimator (DMLC). A 4D computed tomography (CT) scan is used for segmenting tumor anatomy on a reference phase of periodic motion of the tumor. Deformable registration of the 4D CT data is used to generate corresponding anatomical structures on other phases. Preferably, the collimator for each beam position is aligned using the gross tumor volume (GTV) centroid motion corresponding to the periodic motion of the tumor, as determined from the two dimensional (2D) projection of a given beam position. A deliverable IMRT plan is created on the 4D CT image set in which the MLC leaf positions and beam on/off status can vary as a function of respiratory phase by solving a four dimensional optimization problem. The mechanical constraints of the MLC leaves are included in the optimization.

Abstract: A method of continuous real-time monitoring and positioning of multi-leaf collimators during on and off radiation exposure conditions of radiation therapy to account for target motion relative to a radiation beam is provided. A prediction algorithm estimates future positions of a target relative to the radiation source. Target geometry and orientation are determined relative to the radiation source. Target, treatment plan, and leaf width data, and temporal interpolations of radiation doses are sent to the controller. Coordinates having an origin at an isocenter of the isocentric plane establish initial aperture end positions of the leaves that is provided to the controller, where motors to position the MLC midpoint aperture ends according to the position and target information. Each aperture end intersects a single point of a convolution of the target and the isocenter of the isocentric plane.

Abstract: A method and system are disclosed for estimating internal position information of a target in real-time based on a single gantry-mounted x-ray imager and a respiratory signal. The x-ray imaging is done periodically to limit radiation dosage. Initial parameters for the estimation model are determined in a pre-treatment session using four dimensional computed tomography (4D CT) in combination with a respiratory signal acquired from the patient. The model parameters are updated during treatment based on the periodic x-ray image data and the respiratory signal.

Abstract: A method of continuous real-time monitoring and positioning of multi-leaf collimators during on and off radiation exposure conditions of radiation therapy to account for target motion relative to a radiation beam is provided. A prediction algorithm estimates future positions of a target relative to the radiation source. Target geometry and orientation are determined relative to the radiation source. Target, treatment plan, and leaf width data, and temporal interpolations of radiation doses are sent to the controller. Coordinates having an origin at an isocenter of the isocentric plane establish initial aperture end positions of the leaves that is provided to the controller, where motors to position the MLC midpoint aperture ends according to the position and target information. Each aperture end intersects a single point of a convolution of the target and the isocenter of the isocentric plane.