Abstract: The present disclosure provides a system for SMS MRI. During each of a plurality of frames, the system may cause an MRI scanner to apply a plurality of PE steps to each of a plurality of slice locations of a subject to acquire echo signals. A phase modulation magnetic field gradient may be applied during each of at least some of the PE steps in the frame. For each frame, the system may reconstruct an aliasing image representative of the slice locations in the frame based on the corresponding echo signals. The system may also generate a plurality of reference slice images based on the aliasing images. The system may further reconstruct at least one slice image based on the aliasing images and the reference slice images. Each of the slice image may be representative of one of the slice locations in one of the frames.

Abstract: Systems and methods for image reconstruction are provided. The methods may include obtaining a first image sequence of a subject and obtaining an initial input function that relates to a concentration of an agent in blood vessels of the subject with respect to time. The first image sequence may include one or more first images generated based on a first portion of scan data of the subject. The methods may further include, for each of a plurality of pixels in the one or more first images, determining at least one correction parameter associated with the pixel and determining, based on the initial input function and the at least one correction parameter, a target input function The methods may further include generating one or more target image sequences related to one or more dynamic parameters based at least in part on a plurality of target input functions.

Abstract: A system for MRI is provided. The system may obtain a plurality of sets of under-sampled k-space data corresponding to a plurality of frames. Each set of under-sampled k-space data may be acquired simultaneously from a plurality of slice locations of a subject in one of the frames using an MRI scanner. The system may reconstruct a plurality of reference slice images based on the sets of under-sampled k-space data of the plurality of frames. Each of the reference slice images may be representative of one of the slice locations in more than one frame of the frames. The system may further reconstruct a plurality of image series based on the sets of under-sampled k-space data and the reference slice images. Each image series may correspond to one of the slice locations and include a plurality of slice images of the corresponding slice location in the plurality of frames.

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.

Abstract: The disclosure relates to PET imaging systems and methods. The systems may obtain a plurality of PET images of a subject and a CT image acquired by performing a spiral CT scan on the subject. Each gated PET image may include a plurality of sub-gated PET images. The CT image may include a plurality of sub-CT images each of which corresponds to one of the plurality of sub-gated PET images. The systems may determine a target motion vector field between a target physiological phase and a physiological phase of the CT image based on the plurality of sub-gated PET images and the plurality of sub-CT images. The systems may reconstruct an attenuation corrected PET image corresponding to the target physiological phase based on the target motion vector field, the CT image, and PET data used for the plurality of gated PET images reconstruction.

Abstract: A device may include a collimator positioned between a radiation source of a scanner and a bore of the scanner. The bore may include a detecting region configured to accommodate a subject. The collimator may be configured to prevent at least one portion of radiation rays emitted from the radiation source from being incident on the subject. The device may further include a first filter and a second filter. The first filter may be positioned between the radiation source and the collimator. The second filter may be positioned between the collimator and the bore. The first filter and the second filter may be configured to adjust a distribution of radiation impinging upon the subject.

Abstract: The present disclosure provides a system for MRI. The system may obtain a plurality of echo signals relating to a subject that are excited by an MRI pulse sequence applied to the subject. The system may perform a quantitative measurement on the subject based on the plurality of echo signals. The MRI pulse sequence may include a CEST module configured to selectively excite exchangeable protons or exchangeable molecules in the subject, an RF excitation pulse applied after the CEST module configured to excite a plurality of gradient echoes, and one or more refocusing pulses applied after the RF excitation pulse. Each of the refocusing pulses may be configured to excite one or more spin echoes. The one or more spin echoes excited by at least one of the one or more refocusing pulses may include a symmetric spin echo and one or more asymmetric spin echoes.

Abstract: A system for controlling a device is provided. The system may include a remote control device and a safety control device communicating with each other via a wireless connection. The remote control device may be configured to remotely control the device. The remote control device may include a switch, a motion enable unit, and a hand control unit. The motion enable unit may be configured to generate processed information by processing information using a first secret. The hand control unit may be capable of acquiring the processed information from the motion enable device only when the switch is in a closed state. The hand control unit may be configured to transmit the processed information to the safety control device via the wireless connection. The safety control device may include a communication unit and a safety control unit. The communication unit may be configured to receive the processed information via the wireless connection.

Abstract: A system is provided in the present disclosure. The system may acquire a first set of echo signals and a second set of echo signals relating to a subject. The first and the second set may be generated by using an MR scanner to execute a first acquisition and a second acquisition on the subject, respectively. The first acquisition may include at least a first repetition and a second repetition with different repetition times. Each of the first and second repetitions may have a first flip angle. The second acquisition may include at least a third repetition and a fourth repetition with different repetition times. Each of the third repetition and the fourth repetition may have a second flip angle different from the first flip angle. The system may also perform a measurement on the subject based on at least one of the first set or the second set.

Abstract: A method for determining a signal representation of a subject in MRI is provided. The method may include acquiring a plurality of signals of the subject. The plurality of signals may be generated using an MRI device, and each of the plurality of signals may correspond to a set of values in a plurality of signal dimensions of signal acquisition using the MRI device. The method may include determining, among the plurality of signal dimensions, a primary signal dimension and at least one secondary signal dimension, the primary signal dimension being associated with the signal representation. The method may also include determining the signal representation of the subject based on the primary signal dimension, the at least one secondary signal dimension, and the plurality of signals.

Abstract: A radiation treatment system may include a gantry configured to rotate around an object, a treatment head moving with the gantry, a plurality of imaging radiation sources configured to emit imaging beams toward the object, and one or more first detectors configured to detect at least a portion of the imaging beams. When the treatment head is delivering a treatment beam to the object, the plurality of imaging radiation sources and the one or more first detectors may be positioned outside at least a portion of a maximum treatment radiation region so as not to interfere with the treatment beam. At least one of the plurality of imaging radiation sources and the one or more first detectors may be positioned at or near an edge of the maximum treatment radiation region.

Abstract: The present disclosure is related to systems and methods for reconstructing a positron emission tomography (PET) image. The method includes obtaining PET data of a subject. The PET data may correspond to a plurality of voxels in a reconstructed image domain. The method includes obtaining a motion signal of the subject. The method includes obtaining motion amplitude data. The motion amplitude data may indicate a motion range for each voxel of the plurality of voxels. The method includes determining gating data based at least in part on the motion amplitude data. The gating data may include useful percentage counts each of which corresponds to at least one voxel of the plurality of voxels. The method includes gating the PET data based on the gating data and the motion signal. The method includes reconstructing a PET image of the subject based on the gated PET data.

Abstract: An MRI system is provided. The system may obtain a first set of MRI data relating to a subject acquired by an MR scanner in a first acquisition when the subject reaches a first T1 weighting level, and obtain a second set of MRI data relating to the subject acquired by the MR scanner in a second acquisition when the subject reaches a second T1 weighting level different from the first T1 weighting level. The system may also determine a target value of a reference coefficient associated with a first B1 inhomogeneity in the first acquisition and a second B1 inhomogeneity in the second acquisition based on the first and second sets of MRI data.

Abstract: The disclosure relates to PET imaging systems and methods. The systems may execute the methods to obtain an anatomical image and PET data of a subject, and gate the PET data into a plurality of bins. The systems may execute the methods to reconstruct a plurality of gated PET images based on the gated PET data. The systems may execute the methods to determine a motion vector field corresponding to a target respiratory phase with respect to a reference respiratory phase relating to the anatomical image. The systems may execute the methods to obtain a respiratory phase-matched anatomical image for the target respiratory phase by transforming a VOI in the anatomical image based on the motion vector field corresponding to the target respiratory phase with respect to the reference respiratory phase, and reconstructing an attenuation corrected PET image corresponding to the target respiratory phase.

Abstract: A system and method for adapting treatment plan are provided. The method may include: obtaining a planning image of a region of interest relating to a first treatment fraction of a first treatment plan; obtaining a first image of the region of interest relating to a first scan of the region of interest with a first dose level; comparing the planning image with the first image to generate a first comparison result; determining whether the first comparison result satisfies a first replanning condition; causing, in response to a determination that the first comparison result satisfies the first replanning condition, one or more scanners to perform a second scan with a second dose level to provide a second image; and generating a second treatment plan according to the second image, wherein the second dose level is higher than the first dose level.

Abstract: A target assembly for generating radiation may comprise a target, a substrate and a window. The target may be capable of generating first radiation when impinged by a beam. The window may be at least partially permeable to the beam. The window and the substrate may form at least part of a hermetically sealed chamber and the target may be positioned in the chamber. The chamber may be filled with air having a normal or reduced content of oxygen.

Abstract: The present disclosure is related to systems and methods for isocenter calibration. The method includes providing a phantom including a first member and a second member with a fixed position relationship. The method includes acquiring, using a first device, at least one first image of the first member of the phantom. The method includes determining, based on the at least one first image, a first position relationship between a first isocenter of the first device and the first member. The method includes acquiring, using a second device, at least one second image of the second member of the phantom. The method includes determining, based on the at least one second image and the fixed position relationship, a second position relationship between a second isocenter of the second device and the first member. The method includes determining, based on the first position relationship and the second position relationship, a third position relationship between the first isocenter and the second isocenter.

Abstract: Systems and methods for magnetic resonance imaging (MRI) are provided. The systems may obtain a sampling pattern associated with an image sequence. The sampling pattern may be associated with a plurality of phase encoding gradient field values. The systems may also obtain k-space data associated with the image sequence using the sampling pattern. The systems may further reconstruct the image sequence based on the k-space data. The sampling pattern may include a plurality of sampling points. Each of the plurality of sampling points may denote a k-space line associated with the k-space data. Each of the plurality of phase encoding gradient field values may correspond to one single sampling point during a time period associated with at least two consecutive images in the image sequence.

Abstract: The present disclosure relates to systems and methods for reconstructing an image in an imaging system. The methods may include obtaining scan data representing an intensity distribution of energy detected at a plurality of detector elements and determining an image estimate. The methods may further include determining an objective function based on the scan data and the image estimate. The objective function may include a regularization parameter. The methods may further include iteratively updating the image estimate until the objective function satisfies a termination criterion, and for each update, updating the regularization parameter based on a gradient of an updated image estimate. The methods may further include outputting a final image based on the updated image estimate when the objective function satisfies the termination criterion.

Abstract: The present disclosure provides a system and method for medical imaging. The method may include obtaining a treatment plan, a planning image, and one or more treatment images of the subject, wherein the one or more treatment images are generated by performing at least a portion of the treatment plan including delivering at least a radiation beam towards the subject using a radiation device. The method also includes determining primary images of the subject based on the one or more treatment images, and determining inversely-attenuated primary images of the subject by inversely attenuating the primary images to a plane located between the subject and a collimator assembly of the radiation device. The method may further include estimating machine parameters of the radiation device corresponding to the inversely-attenuated primary images.