A method of operating a radiation apparatus is described that selects at least a first angle and a second angle from the set of angles for a first rotation of the gantry. The method generates, using an imaging device mounted to the gantry, a first tracking image of the target from the first angle during the first rotation of the gantry. The method generates, using the imaging device, a second tracking image of the target from the second angle during the first rotation of the gantry. The method performs targeting tracking based on the first tracking image and the second tracking image.

In a continuous arc radiation therapy planning method for planning a radiation therapy session parameterized by a set parameters for control points (CPs) along at least one radiation source arc, a geometric optimization (40) is performed that does not include calculating radiation absorption profiles to generate optimized values for a sub-set of the parameters. After the geometric optimization, a main optimization (42) is performed that includes calculating radiation absorption profiles. The main optimization is performed with the sub-set of parameters initialized to the optimized values from the geometric optimization. The sub-set of parameters optimized by the geometric optimization may include collimator angle parameters for a multileaf collimator (MLC) (58). The geometric optimization may optimize a cost function comprising a sum over the CPs of a per-CP cost function dependent on a target-only region (62) defined as a planning target volume excluding any portion overlapping an organ at risk.

The present disclosure generally relates to a multi-leaf collimator. The multi-leaf collimator may include a set of leaves installed in a cavity, each leaf of the set of leaves having a length along a first direction. At least a portion of the set of leaves may extend beyond the cavity along the first direction. The set of leaves may be arranged along a second direction, the second direction being different from the first direction. A length of a target leaf of the set of leaves may be less than a length of a reference leaf of the set of leaves. The target leaf may be located in an end portion of the set of leaves along the second direction. The length of the set of leaves may conform to the shape of a maximum therapeutic radiation field.

A method of making a treatment plan with a treatment planning system and radiotherapy system are provided. The method includes: acquiring a preset dose distribution scheme; generating at least one radiation dose distribution scheme to be used with the treatment planning system, wherein the treatment plan system is adapted to at least one of beam energy of the radiotherapy system, a size of a collimator of the radiotherapy system, a radiation angle and radiation time of the radiotherapy system; and comparing the at least one radiation dose distribution scheme to be used with the preset dose distribution scheme, and determining, among the at least one radiation dose distribution scheme, a radiation dose distribution scheme that is the closest to the preset dose distribution scheme to make the treatment plan.

It is provided a method for generating a plurality of treatment plans for radiation therapy, each treatment plan specifying weights for a plurality of geometrically defined fluence elements. Each weight defines an amount of radiation fluence, to thereby provide radiation dose to a target volume. The method is performed in a treatment planning system and comprises the steps of: generating a first set of treatment plans; determining a subset of the fluence elements, based on the first set of treatment plans; and generating a second set of at least two treatment plans, wherein the treatment plans only contain weights for the subset of fluence elements.

Disclosed herein are systems and methods for monitoring calibration of positron emission tomography (PET) systems. In some variations, the systems include an imaging assembly having a gantry comprising a plurality of positron emission detectors. A housing may be coupled to the gantry, and the housing may include a bore and a radiation source holder spaced away from a patient scan region within the bore. A processor may be configured to receive positron emission data from the positron emission detectors and to distinguish the positron emission data from the radiation source holder and from the patient scan region. A fault signal may be generated when the positron emission data from the radiation source holder exceeds one or more threshold parameters or criteria.

Systems, devices, and methods for imaging-based calibration of radiation treatment couch position compensations.

A method includes receiving, from a volumetric imager, a first image including a target of a patient. The method further includes receiving a second image including the target of the patient. The method further includes tracking, by a processing device, a position of the target using the first image and the second image by maintaining a fixed alignment between a treatment beam of a linear accelerator (LINAC) and a source and detector pair of the volumetric imager during operation of the LINAC.

Disclosed herein are methods for radiotherapy treatment planning and delivery that use sensor data from one or more target sensors. One variation of a radiotherapy treatment planning method comprises generating a sensor characterization image based on a sensor characterization probability density function (PDF) of a target sensor and calculating a set of firing filters that may be applied to sensor images generated from sensor data acquired during a radiation-delivery session. Additionally, a variation of a radiotherapy treatment planning method comprises generating multiple sensor characterization images based on multiple sensor characterization PDF of multiple target sensors and calculating multiple sets of firing filters for each of the multiple target sensors. The firing filters may be used with sensor images generated from target sensor data acquired from one or more target sensors during a radiation-delivery session to calculate a radiation fluence for delivering therapeutic radiation to a target region.

An x-ray imaging apparatus and associated methods are provided to receive measured projection data in a primary region and measured scatter data in asymmetrical shadow regions and determine an estimated scatter in the primary region based on the measured scatter data in the shadow region(s). The asymmetric shadow regions can be controlled by adjusting the position of the beam aperture center on the readout area of the detector. Penumbra data may also be used to estimate scatter in the primary region.