Abstract: The present disclosure provides a method for processing projection data. The method may include obtaining a first image generated by performing a first scan to a subject by a first imaging device; determining first projection data based on the first image, the first projection data corresponding to a first area of the subject; obtaining second projection data by performing a second scan of the subject using a second imaging device, the second projection data corresponding to a second area of the subject, the first area at least partially overlapping with the second area in an overlapping area; determining registered first projection data by registering the first projection data to the second projection data with respect to the overlapping area; determining scatter component based on the registered first projection data and the second projection data, the scatter component including low-frequency scattered radiation signals.

Abstract: The method may include obtaining a first set of imaging data affording a sagittal view relating to a subject and a first couch supporting the subject. The first couch may have a plurality of first positions reflected in the first set of imaging data as a first conformation. The method may also include determining a displacement field associated with a first set of imaging data with respect to the reference conformation based on the first conformation and a reference conformation. The method may further include adjusting the first set of imaging data with respect to the reference conformation based on the displacement field. In some embodiments, the method may include obtaining an image of the subject with respect to the reference conformation based on the adjusted first set of imaging data.

Abstract: A method for generating a radiation treatment plan is provided. The method may include determining a set of one or more optimization goals for radiation delivery by a therapeutic radiation delivery apparatus. The method may also include determining a plan for radiation delivery from a radiation source of the therapeutic radiation delivery apparatus. The radiation source may be capable of continuously rotating around a subject. The plan may include a plurality of radiation segments. Each radiation segment may be characterized by at least one parameter selected from a start angle, a stop angle, a two-dimensional segment shape, or a segment MU value such that the plurality of radiation segments satisfy the set of one or more optimization goals by superimposing at least two radiation segments from at least two different rotations into a target volume of the subject.

Abstract: The disclosure provides a system for EGRT. The system may include a radiotherapy device for treating a subject. The radiotherapy device may include a scintillation camera that is directed at an ROI of the subject. The subject may be injected with a radioactive tracer or implanted with a radioactive marker before treatment. The ROI may undergo a physiological motion during the treatment. The system may deliver a treatment session to the subject by the radiotherapy device. During the treatment session, the system may acquire a target image of the ROI indicative of a distribution of the radioactive tracer or the radioactive maker in the ROI by the scintillation camera, and adapt a radiation beam to be delivered to the subject with respect to the physiological motion of the ROI by adjusting the radiation beam based on the target image.

Abstract: A system for equalizing a pressure in an ionization chamber of a radiation device is provided. The system may include the ionization chamber including: a chamber housing including one or more chamber walls; a chamber volume inside the chamber housing, the chamber volume being filled with a radiation sensitive material; and a pressure adjustment apparatus operably coupled to the chamber volume via at least one wall of the one or more chamber walls, the pressure adjustment apparatus being configured to equalize a first pressure of the radiation sensitive material inside the chamber volume and a second pressure of ambient air outside the chamber housing.

Abstract: A method and system for using in a two-modality apparatus. The two-modality apparatus comprises a couch with a table top, a first modality unit and a second modality unit. A second image of a target portion of an object when the table top is at a second working position of the second modality unit may be acquired. A second sag of the table top at a second measurement point of the table top according to the second image may be determined based on the image. A difference between a first sag of the table top at a first measurement point of the table top and the second sag may be estimated based on the second sag and standard data. The standard data provides a relationship relating to a sag of the table top positioned between the first modality unit and second modality unit.

Abstract: A radiation system is provided. The radiation system may include a bore accommodating an object, a rotary ring, a first radiation source and a second radiation source mounted on the rotary ring and a processor. The first radiation source may be configured to emit a first cone beam toward a first region of the object. The second radiation source may be configured to emit a second beam toward a second region of the object, the second region including at least a part of the first region. The processor may be configured to obtain a treatment plan of the object, the treatment plan including parameters associated with radiation segments. The processor may be further configured to control an emission of the first cone beam and/or the second beam based on the parameters associated with the radiation segments to perform a treatment and a 3-D imaging simultaneously.

Abstract: System for treatment positioning is provided. The system may include a treatment component, an imaging component, and a couch. The treatment component may include a radiation source that has a radiation isocenter. The couch may be movable between the treatment component and the imaging component, and include a positioning line that has a positioning feature. The system may acquire at least one first image relating to a subject and the positioning line using the radiation source at a set-up position. The system may also acquire at least one second image relating to the subject and the positioning line using the imaging component at an imaging position. The system may further determine a treatment isocenter of a target of the subject based on the at least one second image, and determine a treatment position of the subject based on the first image(s), the second image(s), and the positioning line.

Abstract: A method for delivering radiation treatment may include defining a preliminary trajectory including a plurality of control points. Each control point may be associated with position parameters of a gantry and a couch. The method may also include generating a treatment plan based on the preliminary trajectory by optimizing an intensity and position parameters of a collimator and MLC leaves for each control point. The method may also include decomposing the treatment plan into a delivery trajectory including the plurality of control points. Each of the plurality of control points may be further associated with the optimized intensity, the optimized position parameters of the collimator and the MLC leaves, an output rate, and a motion parameter of each of the gantry, the couch, the collimator, and the MLC leaves. The method may further include instructing a radiation delivery device to deliver the treatment plan according to the delivery trajectory.

Abstract: The present disclosure provides a method for processing projection data. The method may include obtaining a first image generated by performing a first scan to a subject by a first imaging device; determining first projection data based on the first image, the first projection data corresponding to a first area of the subject; obtaining second projection data by performing a second scan of the subject using a second imaging device, the second projection data corresponding to a second area of the subject, the first area at least partially overlapping with the second area in an overlapping area; determining registered first projection data by registering the first projection data to the second projection data with respect to the overlapping area; determining scatter component based on the registered first projection data and the second projection data, the scatter component including low-frequency scattered radiation signals.

Abstract: The present disclosure provides a method for computed tomography (CT) image reconstruction. The method may include obtaining a plurality of projection images of a subject. The plurality of projection images may be generated according to scan data acquired by a CT scanner at a plurality of gantry angles, each of the plurality of projection images corresponding to one of the plurality of gantry angles. The method may also include determining attenuation information of the plurality of projection images. The method may further include reconstructing a CT image of the subject by simultaneously solving correction coefficients of the plurality of projection images such that a difference between estimated attenuation information of the plurality of projection images and the attenuation information of the plurality of projection images is minimized.

Abstract: A method for generating a radiation treatment plan is provided. The method may include determining a set of one or more optimization goals for radiation delivery by a therapeutic radiation delivery apparatus. The method may also include determining a plan for radiation delivery from a radiation source of the therapeutic radiation delivery apparatus. The radiation source may be capable of continuously rotating around a subject. The plan may include a plurality of radiation segments. Each radiation segment may be characterized by at least one parameter selected from a start angle, a stop angle, a two-dimensional segment shape, or a segment MU value such that the plurality of radiation segments satisfy the set of one or more optimization goals by superimposing at least two radiation segments from at least two different rotations into a target volume of the subject.

Abstract: The method may include obtaining a first set of imaging data affording a sagittal view relating to a subject and a first couch supporting the subject. The first couch may have a plurality of first positions reflected in the first set of imaging data as a first conformation. The method may also include determining a displacement field associated with a first set of imaging data with respect to the reference conformation based on the first conformation and a reference conformation. The method may further include adjusting the first set of imaging data with respect to the reference conformation based on the displacement field. In some embodiments, the method may include obtaining an image of the subject with respect to the reference conformation based on the adjusted first set of imaging data.

Abstract: A radiation treatment device may include a first dosimeter and a second dosimeter. Quantum efficiency of the first dosimeter may be lower than quantum efficiency of the second dosimeter. A method for monitoring beam energy may include receiving a first signal generated by a first dosimeter, receiving a second signal generated by a second dosimeter, receiving a third signal generated by the first dosimeter and receiving a fourth signal generated by the second dosimeter. The first signal and the second signal may be associated with a first radiation beam. The second signal and the fourth signal may be associated with a second radiation beam. The method may also include determining whether there is a difference between the beam energy of the first radiation beam and the second radiation beam based on at least one of the first signal, the second signal, the third signal or the fourth signal.

Abstract: A method for adaptive treatment planning is provided. The method may include obtaining a planning image volume of a subject, a treatment image volume of the subject, and a first treatment plan related to the planning image volume of the subject, each of the planning image volume and the treatment image volume including an ROI of the subject. The method may also include registering the planning image volume and the treatment image volume, and determining a first contour of the ROI in the registered planning image volume and a second contour of the ROI in the registered treatment image volume. The method may also include evaluating whether an error exists in at least one of the registration or the contour determination based on the first contour and the second contour, and determining a second treatment plan with respect to the treatment image volume based on the evaluation result.

Abstract: The present disclosure provides a method for imaging of moving subjects. The method may include determining a motion range of a region of interest (ROI) of a subject in an axial direction. The method may also include causing a radiation source to emit, at each of a plurality of axial positions relative to the subject, radiation beams to the ROI to generate an image frame of the ROI. The radiation beams corresponding to the plurality of axial positions may jointly cover the motion range of the ROI in the axial direction. The method may further include determining a position of the ROI in the axial direction based on the image frames of the ROI, and determining, based on the positions of the ROI in the axial directions, at least one time bin in which therapeutic beams are to be emitted to the ROI.

Abstract: A method for correcting projection images in CT image reconstruction is provided. The method may include obtaining a plurality of projection images of a subject. Each of the plurality of projection images may correspond to one of the plurality of gantry angles. The method may further include correcting a first projection image of the plurality of projection images according to a process for generating a corrected projection image. The process may include performing, based on the first projection image and a second projection image of the plurality of projection images, a first correction on the first projection image to generate a preliminary corrected first projection image. The process may also include performing, based on at least part of the preliminary corrected first projection image, a second correction on the preliminary corrected first projection image to generate a corrected first projection image corresponding to the first gantry angle.

Abstract: The present disclosure provides a system and method for dose measurement in radiation therapy. The method may include obtaining a beam model and a detector model related to a radiation device, and a reference image and a treatment plan related to the subject, and determining a synthetic image based on the beam model, the detector model, and the reference image. The method may also include obtaining a treatment image by performing at least a portion of the treatment plan including delivering at least a radiation beam toward the subject using the radiation device, and determining one or more scaling factors. The method may further include determining a synthetic estimate of the treatment image based on the synthetic image and the one or more scaling factors. The method may further include estimating radiation dose deposition based on the treatment image and the synthetic estimate of the treatment image.

Abstract: The present disclosure provides a method for synthesizing a projection image that represents a subject or object irradiated by X-rays from a radiation source. The method may include dividing an energy spectrum of the X-rays into one or more energy bins; determining a projection value of at least one pixel; determining a weighting coefficient corresponding to an energy bin based on a variation of the energy spectrum of the X-rays; and determining a weighted projection value of the at least one pixel based on the projection value of the at least one pixel and the weighting coefficient corresponding to the energy bin. The method may further include determining a pixel value of the at least one pixel based on the weighted projection values of the at least one pixel that correspond to all the one or more energy bins.

Abstract: The present disclosure provides systems and methods for processing a 3D image. A method may include for an orientation of the 3D image, obtaining, from the 3D image, a plurality of slices of the orientation; processing the plurality of slices of the orientation by applying a conversion model; and determining a converted 3D image of the orientation based on the plurality of processed slices of the orientation.