Abstract: A method for controlling filament current of a computed tomography (CT) tube includes: detecting a present tube current of the CT tube and assigning the present tube current to a feedback value, calculating a difference between a set value of the tube current and the feedback value and assigning the difference to an error value, assigning a target upper bound value to a present filament current when the error value is greater than an first error threshold, and assigning a target lower bound value to the present filament current when the error value is less than a second error threshold, wherein the target upper bound value is greater than the target lower bound value, the first error threshold is greater than 0, and the second error threshold is less than 0.

Abstract: Impedance matching circuits and methods for radio frequency (RF) transmission coil are disclosed. An example impedance matching circuit includes a coil matching circuit, a RF power detection circuit, and a spectrometer. The spectrometer outputs an output voltage reversely applied on a varactor diode of the coil matching circuit. An impedance of the coil matching circuit is changed based on the output voltage. The spectrometer outputs a RF transmission signal to the RF power detection circuit, receives a power of a RF reflected signal corresponded to the output voltages. The spectrometer receives powers of different RF reflected signals corresponded to different output voltages, and assigns an output voltage corresponded to a minimum power of the RF reflected signals as an impedance matching voltage, where an equivalent impedance of the coil matching circuit and the RF transmission coil matches with an impedance of RF transmission lines.

Abstract: A method for processing metal artifacts in a CT image is provided. The method may comprise: performing a first metal artifact processing on the original image to obtain a first processed image COR1 and extracting the high frequency portion of the first processed image COR1 to obtain a first high-frequency image COR1HF; performing a second metal artifact processing on the original image to obtain a second processed image COR2 and extracting the high frequency portion of the processed image COR2 second to obtain a second high-frequency image COR2HF; perform a weighted combination the first processed image COR1, the first high-frequency image COR1HF and the second high-frequency image COR2HF by using a weighting function W to obtain a result image CORImp containing no metal artifact, but information of area near the metal artifact.

Abstract: A method and a PET apparatus are provided. According to an example of the method, a saturation indicia of a target detector may be determined through simulating emission of a ? photon to the target detector. The target detector is any one of SiPM detectors of a PET apparatus. The saturation indicia is for designating a maximum output voltage after amplifying an output of the target detector through a VGA when one ? photon is received by the target detector. The target VGA is a VGA corresponding to the target detector. By comparing an output voltage of the target VGA and the saturation indicia, it may determine that the target detector received a saturation event if the output voltage of the target VGA is higher than the saturation indicia. An amplifier gain of the target VGA may be adjusted until an amount of the saturation events detected by the target detector in unit time satisfies a pre-determined threshold.

Abstract: A detector system for a CT scanner is provided. The detector system may include a plurality of detector modules. Each of the detector modules may include a supporting frame, two or more detectors and an interface board. A supporting frame may be connected to a casing of the detector system. Detectors may be mounted onto a supporting frame and may convert an X-ray beam within a CT scanner into an electrical signal. An interface board may be disposed in an outer side of a supporting frame away from the focus of an X-ray tube, and may be electrically connected to a plurality of detectors through a connector, so as to provide a control signal and a power supply to the detectors, and to transmit a digital signal outputted by the detectors to a backplane of the detector system through an output line.

Abstract: Methods of generating a gradient waveform, gradient waveform generators and magnetic resonance imaging systems are provided. In one aspect, a first digital value is obtained by quantizing and coding spatial position information of a voxel of a subject according to the number of preset quantization bits, wherein the number of the quantization bits are more than the number of allowed input bits for a DAC; a second digital value is determined to be inputted into the DAC according to the first digital value and the number of the allowed input bits for the DAC; a quantization error is determined according to the first digital value and the second digital value; an error accumulating value is updated by accumulating the quantization error to the error accumulation value; the second digital value corrected according to the error accumulation value; and the corrected second digital value is inputted into the DAC.

Abstract: A method for modulating x-ray radiation dose in CT scan is disclosed. The method may include: acquiring x-ray attenuation information of each Z position within a planned scanning sequence for a scan region of a subject from data of a finished scanning sequence for the subject; and then, based on the acquired x-ray attenuation information, performing dose modulation with respect to the XY scanning profile at each Z position within the planned scanning sequence. The finished scanning sequence can be an axial and/or helical scanning sequence for a scan region wholly or partially same as the scan region and has been performed earlier. The Z position may include a position in Z direction extending from head to foot of the subject or conversely. The XY scanning profile may include a scanning profile of the subject which is vertical to Z direction.

Abstract: A method for restoring CT scan data is disclosed. The method may comprise: building a data collecting model with respect to a specific direction of a detector based a response curve of the detector. In some examples, the specific direction can indicate a channel direction and a slice direction of the detector. During a CT scanning, based on the data collecting model, X-ray intensity values detected by the detectors in the specific direction can be acquired. A function can be determined such that it satisfies the data collecting model, a continuity condition and a boundary condition, An X-ray intensity value can be obtained by substituting the coordinate value of a point in the specific direction into the function.

Abstract: A timing method and a timing device are disclosed. A Gray code count output may be obtained by performing a Gray code count on a basic clock. Then m number of sub-clocks may be obtained by separately performing a phase shift on a least significant bit output of the Gray code count output, where a phase difference ? between each of the m number of sub-clocks and the least significant bit output may satisfy: ?=n×? and ??90°, 180° may be divisible by ? with no remainder, and n may be an integer greater than 0 and less than 180°/?. If 90° is divisible by ? with no remainder, m=180/??2; and if 90° is divisible by ? with a remainder, m=180/??1. When a predetermined event occurs, a timing result of the predetermined event may be obtained according to the Gray code count output value, outputs of the m number of sub-clocks, a period of the basic clock, and the ?.

Abstract: A method and a device for dose modulated X-ray scanning, where, according to an example of the method, a theoretical X-ray scanning dose for a scanning region may be calculated according to a target image quality standard set for the scanning region and a reference data level determined for the scanning region. Then, an X-ray attenuation difference between each data level corresponding to the scanning region and the reference data level may be calculated according to the theoretical X-ray scanning dose. In this way, a data level where the X-ray attenuation difference with the reference data level is higher than a threshold may be selected out from the data levels corresponding to the scanning region as a target to be de-noised, and a noise reduction may be performed for the target to be de-noised.

Abstract: An apparatus for recognizing a position of a crystal in a nuclear detector, including: a silicon semiconductor detector array arranged in a crystal array in the nuclear detector, where each row/or column of silicon semiconductor detectors is configured to output a sum of voltages outputted by the silicon semiconductor detectors in the row/or column at a row/or column signal output end; row signal comparing modules, one to one correspondingly connected to each row signal output end and configured to obtain a row comparison result for each row of silicon semiconductor detectors; column signal comparing modules, one to one correspondingly connected to each column signal output end and configured to obtain a column comparison result for each column of silicon semiconductor detectors; and a crystal position recognizing module configured to recognize a position of a crystal hit by a photon according to each row comparison result and each column comparison result.

Abstract: A three-dimensional cardiac image segmentation method and apparatus are provided according to examples of the present disclosure. The method includes: searching from layers of cardiac computerized tomography CT images to obtain a layer of cardiac CT image located between a heart bottom portion and a heart upper portion as a first key layer; searching on the first key layer to obtain a boundary of the heart as a contour of the heart bottom portion, and generating a curved surface model based on the contour of the heart bottom portion and a lowest point of the heart bottom portion as a heart bottom model; searching layers of cardiac CT images above the first key layer to obtain boundaries of the heart as a contour of the heart upper portion, and generating a curved surface model based on the contour of the heart upper portion as a heart upper model.

Abstract: A method for setting a scanning protocol and an apparatus thereof are provided. The method includes: creating a plain film positioning image; receiving a point or a line or a region of interest on the plain film positioning image input by an operator; generating a region to be matched, based on the point or the line or the region of interest; determining whether there is pre-stored reference image having a matching degree greater than a preset threshold by comparing pre-stored reference images with the region to be matched; obtaining a reference image in the case that the reference image has a matching degree greater than the preset threshold; selecting a scanning protocol corresponding to the reference image based on a preset correspondence between reference images and scanning protocols; and completing a setting of the scanning protocol in the case that there is the scanning protocol corresponding to the reference image.

Abstract: The present invention provides a method for spine position detection, comprising: obtaining 2D geometrical configuration of a current vertebra body selected from a plurality of vertebra bodies visible in an image on a sagittal plane defined by a horizontal component of an initial point, a geometrical template being applied to the current vertebra body and the 2D geometrical configuration of the current vertebra body being adjusted by a predetermined correlation evaluation; searching adjacent edge points of next vertebra body corresponding to a number of edge points of the current vertebra body by identifying the gradient values along the direction substantially perpendicular to the edge of the current vertebra body based on the adjusted 2D geometrical configuration of the current vertebra body; calculating height of an intervertebral disc located between the current vertebra body and the next vertebra body based on an average of the distances between the edge points of the current vertebra body and the corres

Abstract: A method includes: collecting projection data and recording electrocardiogram data when computed tomographic scanning is performed on a patient, selecting, from the projection data and based on the electrocardiogram data, first projection data related to each cardiac pixel in a same phase, and reconstructing, based on the first projection data, an image of the related cardiac pixel, to obtain a cardiac image; determining, based on the electrocardiogram data, a reconstruction phase of each reconstruction pixel in a first reconstruction region, where the first reconstruction region is an image region selected along the patient's head-to-foot direction from the cardiac image; and selecting, based on the reconstruction phase of each reconstruction pixel and from the projection data, second projection data related to the reconstruction pixel in the reconstruction phase, and reconstructing, based on the second projection data, an image of the reconstruction pixel.

Abstract: A method and an apparatus for scanning with a lowered dose are provided. The method includes: determining a dynamic changing model of a prepatient collimator according to a rotation angle of a tube in a scanning mode; in a case that the scanning mode is a normal scan, controlling an opening angle of the prepatient collimator according to the dynamic changing model of the prepatient collimator at an initial stage and an end stage of the normal scan; and in a case that the scanning mode is a scan with phase control, controlling an opening angle of the prepatient collimator according to the dynamic changing model of the prepatient collimator at an initial stage and an end stage of a phase of the scan with phase control.

Abstract: A method and a device for balancing a CT gantry device are provided. The method includes: obtaining a fluctuation chain of pulses generated in one revolution of the CT gantry and obtained when the CT gantry collects data; obtaining an eccentric angle of a center of mass according to the fluctuation chain, and calculating a magnitude of imbalance; and adjusting weight at a weight counterbalancing position according to the eccentric angle and the magnitude of imbalance, to locate the center of mass at the rotation center. The device includes a data collection unit for collecting a fluctuation chain, and a processor for obtaining an eccentric angle of a center of mass, and calculating a magnitude of imbalance; and the processor adjusts weight at the weight counterbalancing position according to the eccentric angle and the magnitude of imbalance, to locate the center of mass at the rotation center.

Abstract: A method for controlling scanning preparation includes: obtaining a first scanning protocol of a current CT examination, controlling a CT scanner to perform a scanning preparation for a first scanning series according to the first scanning protocol; in case that there are one or more subsequent scanning series, controlling CT scanner to perform scanning preparations for the subsequent scanning series according to the first scanning protocol, where for each subsequent scanning series, the scanning preparation is performed during time interval between end of exposure of scanning series previous to the subsequent scanning series and starting of the subsequent scanning series; and obtaining a second scanning protocol of next CT examination and controlling the CT scanner to perform a scanning preparation for a first scanning series according to the second scanning protocol.

Abstract: A method for calculating a motion vector field (MVF) in a reconstructed CT scan image, comprises: determining a region of interest (ROI) based on a vessel centreline in a first reconstructed CT scan image, wherein a motion vector field (MVF) for the ROI is to be calculated; determining at least two time control points for calculating the MVF; calculating a motion level factor of the ROI; calculating motion amounts of the MVF corresponding to each of the time control points; determining the direction of the MVF of the ROI; and calculating the MVF of the ROI according to the motion level factor, the motion amounts of the MVF corresponding to each of the time control points and the direction of the MVF.

Abstract: In an example, a method and apparatus for obtaining an image mask is provided. After a magnitude image and a phase image of a to-be-processed image is obtained, magnitude coherent data of each pixel point in the magnitude image and phase coherent data of each pixel point in the phase image may be calculated. Then, a binarization threshold processing may be performed on the magnitude coherent data of each pixel point in the magnitude image to obtain a magnitude image mask. A binarization threshold processing may be performed on the phase coherent data of each pixel point in the phase image to obtain a phase image mask. In this way, an image mask of the to-be-processed image may be obtained by using the magnitude image mask and the phase image mask.