Abstract: A system and method for MRI are provided. a plurality of RF parameters for an MRI scan, using an MRI scanner, of a subject may be obtained. A first power loss and a first current square factor of the RF coil assembly under an unloaded condition of the MRI scanner may be determined based on the plurality of RF parameters. A total power loss of the MRI scan and a second current square factor of the RF coil assembly during the MRI scan may be determined based on the plurality of RF parameters. A second power loss of the RF coil assembly during the MRI scan may be determined based on the first power loss, the first current square factor, and the second current square factor. A SAR of the subject during the MRI scan may be determined based on the total power loss and the second power loss.

Abstract: The present disclosure relates to systems and methods for medical imaging. The systems may obtain an initial image of an object. The initial image may include a first region of interest (ROI) and one or more second ROIs. The systems may determine, based on the initial image, a first position corresponding to the first ROI and one or more second positions each of which corresponds to one of the one or more second ROIs. The systems may obtain scan data of the object by causing an imaging device to scan the object based on the first position and the one or more second positions. The systems may determine an injection parameter of a drug that is injected into the object based on the scan data. The systems may generate a target image of the object based on the injection parameter and the scan data of the object.

Abstract: The present disclosure provides a system for MRI. The system may obtain a plurality of auxiliary signals and a plurality of imaging signals collected by applying an MRI pulse sequence simultaneously to a plurality of slice locations of a subject. For each of at least one target slice location of the plurality of slice locations, the system may generate at least one target image of the target slice location based on the plurality of auxiliary signals and the plurality of imaging signals. During the application of the MRI pulse sequence, phase modulation may be applied to at least one of the plurality of slice locations so that the plurality of slice locations have different phases during the readout of at least one of the plurality of imaging signals.

Abstract: The present disclosure is related to a microwave source. The microwave source may include a cathode heater and a thermionic emitter. The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater. At least a portion of the second component of the cathode heater may be in contact with the thermionic emitter.

Abstract: A method for magnetic resonance imaging (MRI) may include obtaining a plurality of first magnetic resonance (MR) data sets related to a region of interest (ROI) of a subject. The plurality of first MR data sets may be collected based on two or more different values of a scan parameter. The method may also include determining a plurality of second MR data sets based on the plurality of first MR data sets. Each of the plurality of second MR data sets may correspond to at least two of the plurality of first MR data sets. The method may also include generate, based on the plurality of second MR data sets, a plurality of T1 weighted images of the ROI each of which corresponds to a target time point.

Abstract: A method and a system for positron emission tomography (PET) imaging may be provided. Scan data of an object in a first time period of a PET scan of the object may be obtained. A reference image of the object may be also obtained. The reference image may be reconstructed based on reference scan data in a second time period of the PET scan. A target image of the object in the first time period may be generated using an image reconstruction model based on the scan data in the first time period and the reference image of the object.

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 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: The present disclosure relates to a system and method for locating a target subject associated with an X-ray system. The X-ray system may include an X-ray source, a detection component, an arm, and a platform. The X-ray system may also include a first positioning component, a second positioning component, or a third positioning component. The first positioning component may be configured to determine a target point where a region of interest (ROI) of the target subject locates. The second positioning component may be configured to locate the target subject. The third positioning component may be configured to obtain location information of a target device associated with the target subject in real-time.

Abstract: A method may include obtaining image data of a subject acquired by an imaging device. The method may also include determining one or more characteristics associated with a body part of the subject from the image data. The one or more characteristics of the body part of the subject may include at least one of position information of the body part in the subject, geometric morphology information of the body part, water content information, or fat content information. The method may also include determining, based on one or more characteristics associated with the body part, values of one or more individualized parameters corresponding to the subject. The method may further include causing the imaging device to perform an imaging scan on the subject according to the values of the one or more individualized parameters.

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 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: 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 reconstruction are provided. A method may include obtaining image data that includes information of a plurality of coincidence events; for each of the plurality of coincidence events, identifying, based on the information of the coincidence event, identities of two original scintillator elements at each of which a photon of the coincidence event was detected; obtaining a depth of interaction (DOI) of each photon of the coincidence event within one original scintillator element of the two original scintillator elements; and determining, based on the identities and the DOIs of the two original scintillator elements, identities of two corrected scintillator elements each of which corresponds to an original scintillator element of the two original scintillator elements; and generating a reconstructed image based on the identities of two corrected scintillator elements of each of the plurality of coincidence events.

Abstract: The systems and method for processing scanning data of a scanning object are provided. The method may include acquiring, in a scanning process, at least two target phases of a motion of the scanning object, wherein the scanning process involves multiple data acquisition time points each of which corresponds to a scanning data set; identifying at least two first time periods during the scanning process, each first time period corresponding to one of the two target phases; determining a second time period that encloses the at least two first time periods; and retrieving once, from the multiple scanning data sets, second scanning data sets for reconstructing phase images each of which corresponds to one target phase, the second scanning data sets being acquired at second data acquisition time points of the multiple data acquisition time points within the second time period.

Abstract: A method may include obtaining a feedback or a reference value of a tube voltage applied to a radiation source of a radiation device for generating radiation rays. The method may also include determining, based on the feedback or the reference value of the tube voltage, a specific value of a focusing parameter associated with a focusing device of the radiation device. The method may further include causing the focusing device to shape a focus of the radiation rays according to the determined value of the focusing parameter. The focus of the radiation rays may satisfy an operational constraint under the specific value of the focusing parameter.

Abstract: Systems and methods for motion correction in medical imaging are provided in the present disclosure. The systems may obtain at least two image sequences relating to a subject. Each of the at least two image sequences may be reconstructed based on image data that is acquired by a medical imaging device during one of at least two time periods. The subject may undergo a physiological motion during the at least two time periods. The systems may generate, based on the at least two image sequences, at least one corrected image sequence relating to the subject by correcting, using a motion correction model, an artifact caused by the physiological motion.

Abstract: A method and system for metal artifacts correction are provided. The method may include obtaining an image to be processed including metal portion; determining initial projection data by performing data restoration on the metal portion of the image to be processed; determining target projection data by filtering the initial projection data; and determining a target image based on the target projection data.

Abstract: A radiation measurement device may be provided. The radiation measurement device may comprise a scattering component and a first detector. The scattering component may be located between a radiation source of an imaging device and the first detector, and configured to scatter first radiation rays emitted by the radiation source into scattering rays. The first detector may be configured to collect first measurement data by detecting at least a portion of the scattering rays, the first measurement data reflecting an operation status of the radiation source.

Abstract: A high voltage generator is provided. The high voltage generator includes an inverter bridge including a first bridge leg and a second bridge leg, a first resonant branch coupled in series to the first bridge leg, a transformer coupled in series between the first resonant branch and the second bridge leg, a second resonant branch coupled in series with the transformer, and a rectifier circuit coupled with the transformer for providing an output voltage to an X-ray source.