Abstract: Pulse generators and radiation systems having the same are provided. A pulse generator may include a shielding device and a control device operably connected with the shielding device. The control device may be configured to control the shielding device to intermittently shield radiation emitted from the radiation source to produce pulsed radiation.

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 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: A method for determining a deformation measurement of a couch in a medical procedure may include determining a first deformation measurement of the couch at a reference point, the first deformation measurement corresponding to a first working position of the couch. The method may also include determining a second deformation measurement of the couch at the reference point, the second deformation measurement corresponding to a second working position of the couch. The method may further include determining a difference between the first deformation measurement and the second deformation measurement and causing an adjustment of one of the first working position and the second working position of the couch based on the difference between the first deformation measurement and the second deformation measurement.

Abstract: A method for correcting PET data includes acquiring first PET data at a time interval. The method also includes acquiring a first normalization coefficient corresponding to the first PET data. The method also includes determining a scale factor based at least partially on the first normalization coefficient. The method also includes determining second PET data based on the first PET data, the scale factor, and the second normalization coefficient. The method also includes determining a first dead time correction coefficient corresponding to the second PET data. The method also includes determining third PET data based on the second PET data and the first dead time correction coefficient. The method further includes reconstructing a first image based on the third PET data.

Abstract: The present disclosure relates to a system for PET imaging. The system may include a first device and a second device. The first device may include a first scanning channel. The second device may include a second scanning channel connected to the first scanning channel, a heat generating component, and a cooling assembly configured to cool the heat generating component, wherein the cooling assembly may include an inlet chamber and a return chamber, the heat generating component may be closer to a first side of the second device than at least one of the inlet chamber or the return chamber, and the first side of the second device may face the first device.

Abstract: Methods and systems for signal processing in molecular imaging. The system may include at least one storage device including a set of instructions and at least one processor in communication with the storage device. The at least one processor may obtain a first signal that is acquired by sampling, according to a first sampling frequency, an electrical signal of a detector. The at least one processor may also generate, based on the first signal and a target machine learning model, a second signal, the second signal corresponding to a second sampling frequency that is different from the first sampling frequency. The target machine learning model may specify a target mapping between the first signal and the second signal. The at least one processor may further generate an image based on the second signal.

Abstract: An image processing method is provided, including: obtaining image data of a cavity wall of an organ; unfolding the cavity wall; and generating an image of the unfolded cavity wall. The unfolding of the cavity wall may include: obtaining a mask and a centerline of the organ; obtaining a connected region of the mask; dividing the connected region into at least one equidistant block; determining an orientation of the equidistant block in a three-dimensional coordinate system including a first direction, a second direction and a third direction; determining an initial normal vector and an initial tangent vector of a center point of the centerline; assigning a projection of the initial normal vector to a normal vector of a light direction of the center point; assigning the third direction or an reverse direction of the third direction to a tangent vector of the light direction of the center point.

Abstract: A method may include identifying a time window of a procedure. The method may also include obtaining operational information of the time window. The operational information may include a limit of pulse repetition frequency (PRF) acceleration and a plurality of preliminary radio frequency (RF) PRFs. The method may also include determining a plurality of updated RF PRFs by updating the plurality of preliminary RF PRFs. A rate of variation between any two adjacent updated RF PRFs may be less than or equal to the limit of PRF acceleration. The method may also include causing an RF source to generate electromagnetic waves at the plurality of updated RF PRFs in the time window.

Abstract: A system and method for image reconstruction are provided. A first region of an object may be determined. The first region may correspond to a first voxel. A second region of the object may be determined. The second region may correspond to a second voxel. Scan data of the object may be acquired. A first regional image may be reconstructed based on the scan data. The reconstruction of the first regional image may include a forward projection on the first voxel and the second voxel and a back projection on the first voxel.

Abstract: A system includes a storage device storing a set instructions and a processor in communication with the storage device, wherein when executing the set of instructions, the processor is configured to cause the system to obtain raw data. The processor may also be configured to cause the system to determine one or more reconstruction-related algorithms and determine one or more containers for the one or more reconstruction-related algorithms. Each of the one or more containers may correspond to at least one of the one or more reconstruction-related algorithms. The system may also be configured determine a reconstruction flow based on the one or more containers and process the raw data according to the reconstruction flow to generate a target image.

Abstract: The present disclosure provides a method and system for processing multi-modality images. The method may include obtaining multi-modality images; registering the multi-modality images; fusing the multi-modality images; generating a reconstructed image based on a fusion result of the multi-modality images; and determining a removal range with respect to a focus based on the reconstructed image. The multi-modality images may include at least three modalities. The multi-modality images may include a focus.

Abstract: Systems and methods for image segmentation are provided. A system may obtain a first image of a subject. The system may obtain non-image information associated with at least one of the first image or the subject. The system may further determine a region of interest (ROI) of the first image based on the first image, the non-image information, and an image segmentation model.

Abstract: The present disclosure provides methods and systems for dose distribution prediction. The methods comprise obtaining historical state information and current state information of a target subject. The current state information may reflect the state of the target subject in a current treatment fraction, and the historical state information may reflect the state of the target subject prior to the current treatment fraction. The methods also comprise determining a feature parameter of at least one optimization target with respect to the current treatment fraction, and predicting a current dose distribution to be used in the current treatment fraction based on at least part of the historical state information, the current state information, and the feature parameter of the at least one optimization target using a dose prediction model, the dose prediction model being a trained machine learning model.

Abstract: The present disclosure provides a magnetic resonance imaging (MRI) device. The MRI device may include a main magnet configured to generate a main magnetic field. The main magnet may form an accommodation space configured to accommodate a target object. The main magnet may include at least one group of main field coils. A direction of the main magnetic field generated by the at least one group of main field coils may form a preset angle with an axial direction of the accommodation space. The at least one group of main field coils may include a first group of main field coils and a second group of main field coils that are arranged oppositely along a radial direction of the accommodation space. Each of the first group of main field coils and the second group of main field coils may bend towards each other.

Abstract: A housing in an imaging apparatus is provided. The imaging apparatus may include a Magnetic Resonance (MR) component and a Positron Emission Tomography (PET) component that includes a plurality of detectors. The housing may include one or more enclosed spaces configured to accommodate the plurality of detectors of the PET component. Each of the one or more enclosed spaces is defined by one or more walls.

Abstract: A method for data acquisition in PET may be provided. The method may include obtaining, based on outputs of multiple pairs of detectors of a Positron Emission Tomography (PET) scanner, coincidence events corresponding to multiple LORs. The outputs of the multiple pair of detectors may be acquired during a PET scan on a subject. The method may also include determining, based on a count of coincidence events corresponding to each LOR of at least a portion of the multiple LORs, a detection rate corresponding to the LOR.

Abstract: The present disclosure is related to systems and methods for controlling an imaging device. The system may include an imaging device, a voice processing device, and a terminal. The imaging device may be configured to image a subject. The voice processing device may be configured to receive a first voice signal from or transmit a second voice signal to the subject when the subject is positioned within the imaging device. The terminal may be configured to receive a third voice signal from or transmit a fourth voice signal to a user.

Abstract: An electron gun may include a cathode with an emitting surface configured to emit electrons. The cathode may include a through hole that goes through the emitting surface and is configured to allow back-streaming electrons of the emitted electrons to pass through. The electron gun may also include an anode configured to attract the emitted electrons from the cathode to the anode and focus the emitted electrons into an electron beam. The electron gun may also include a grid structure configured to facilitate the focusing of the emitted electrons, the grid structure being positioned corresponding to the through hole.

Abstract: A method for image stitching is provided. The method may include obtaining a reference image of a first portion of a subject and a target image of a second portion of the subject, and determining at least one pair of feature points based on a preliminary registration accuracy. The first and second portions may at least partially overlap with each other. Each pair may include a reference feature point in the reference image and a target feature point in the target image that matches the reference feature point. For each pair, the method may further include determining an updated pair of feature points based on a superior registration accuracy higher than the preliminary registration accuracy and a neighboring region of the target feature point of the pair. The method may further include generating a stitched image based on the at least one updated pair.