Disclosed herein is a method of characterising physical properties of an attenuating element in a radiotherapy device having a radiotherapy radiation source and a radiotherapy radiation detector on respective sides of the attenuating element. The method comprises obtaining an average detected radiotherapy radiation intensity at two or more locations around the attenuating element, comparing the detected intensity at one location with the average intensity, and characterising a corresponding physical property based on the comparison.

Described are devices, systems, and methods for modulating the spectral energy distribution produced by an x-ray source via control of the energy of the x-ray-generating electron beam, e.g., for energy-modulated radiation therapy or other purposes. In some embodiments, such energy modulation is achieved by an add-on device to a linear accelerator. Also disclosed are computational methods and computer program products for planning energy-modulated therapy.

Described are devices, systems, and methods for modulating the spectral energy distribution produced by an x-ray source via control of the energy of the x-ray-generating electron beam, e.g., for energy-modulated radiation therapy or other purposes. In some embodiments, such energy modulation is achieved by an add-on device to a linear accelerator. Also disclosed are computational methods and computer program products for planning energy-modulated therapy.

A radiation therapy system comprising a therapeutic radiation system (e.g., an MV X-ray source, and/or a linac) and a co-planar imaging system (e.g., a kV X-ray system) on a fast rotating ring gantry frame. The therapeutic radiation system and the imaging system are separated by a gantry angle, and the gantry frame may rotate in a direction such that the imaging system leads the MV system. The radiation sources of both the therapeutic and imaging radiation systems are each collimated by a dynamic multi-leaf collimator (DMLC) disposed in the beam path of the MV X-ray source and the kV X-ray source, respectively. In one variation, the imaging system identifies patient tumor(s) positions in real-time. The DMLC for the imaging radiation source limits the kV X-ray beam spread to the tumor(s) and/or immediate tumor regions, and helps to reduce irradiation of healthy tissue (e.g., reduce the dose-area product).

An imaging apparatus comprises a rotatable gantry system positioned at least partially around a patient support; a first source of radiation coupled to the rotatable gantry system, the first source of radiation configured for imaging radiation; a second source of radiation coupled to the rotatable gantry system; and a first radiation detector coupled to the rotatable gantry system and laterally movable relative to a central beam of the first source of radiation to receive radiation from at least the first source of radiation over various fields of view. Alternative configurations of the imaging apparatus and methods of using the imaging apparatus are also provided.

A radiation delivery system and method of operation are described. The method includes modulating a sub-beam intensity of a radiation beam generated by a radiation source across a plurality of sub-beams that subdivide a fluence field into a two-dimensional (2D) grid, and delivering a plurality of independent two-dimensional (2D) sub-beam intensity patterns from a plurality of angles while the radiation source is moved continuously.

Systems and method for generating and executing volumetric modulated arc therapy (“VMAT”) plans are provided. In some aspects, the method includes receiving a representation of a subject comprising information related to target and non-target volumes of interest, and generating an objective function based on the representation of the subject, wherein the objective function accounts for dynamic collimator rotation. The method also includes performing an iterative optimization process, using the objective function, to generate a dynamic collimator VMAT plan, and generating a report in accordance with the dynamic collimator VMAT plan.

Methods of treatment trajectory optimization for radiotherapy treatment of multiple targets include determining beam's eye view (BEV) regions and a BEV region connectivity manifold for each target group of a plurality of target groups separately. The information contained in the BEV regions and the BEV region connectivity manifolds for all target groups is used to guide an optimizer to find optimal treatment trajectories. To improve the visibility of insufficiently exposed voxels of planning target volumes (PTVs), a post-processing step may be performed to enlarge certain BEV regions, which are considered for exposing during treatment trajectory optimization.

Methods of beam angle optimization for intensity modulated radiotherapy (IMRT) treatment include determining beam's eye view (BEV) regions and a BEV region connectivity manifold by evaluating dose response of each region of interest for each vertex in a delivery coordinate space (DCS). The information contained in the BEV regions and the BEV region connectivity manifold is used to guide an optimizer to find optimal field geometries in the IMRT treatment. To improve the visibility of insufficiently exposed voxels of planning target volumes (PTVs), a post-processing step may be performed to enlarge certain BEV regions, which are considered for exposing during treatment trajectory optimization.

A method of measuring a rotational position of an assembly with circumferential ferromagnetic teeth includes applying an excitation signal for a cycle to an actuator, the cycle causing a first rotational displacement of a first ferromagnetic tooth from a first rotational position to a second rotational position and a second rotational displacement of a second ferromagnetic tooth from the second rotational position to a third rotational position. The method further includes measuring a plurality of first signal outputs from a magnetoresistive sensor during the cycle; determining one or more signal offset values based on the plurality of first signal outputs; applying the signal excitation for a portion of a second cycle to the actuator; measuring second signal outputs from the magnetoresistive sensor; generating corrected signals by modifying the second signal outputs with the signal offset values; and, based on the corrected signals, determining a rotational position of the assembly.