Abstract: A method and device for processing CT data in a CT system are provided. According to an example of the method, when an upper limit of a data transmission bandwidth of a CT machine is determined, an amount of scan data collected per unit time by the CT machine may be taken as a data acquisition amount per unit time and a first ratio of the data acquisition amount per unit time to the upper limit of the data transmission bandwidth may be determined. In this way, a compression strategy and a decompression strategy may be determined according to the first ratio.

Abstract: Methods, devices and a machine-readable storage medium for denoising a Computed Tomography (CT) image are provided. In one aspect, a method of denoising a CT image includes: generating an original CT image according to raw data which is obtained by scanning a subject, where a pixel count of the original CT image is greater than a preset target pixel count; obtaining a denoised image by denoising the original CT image; and obtaining a target image as a CT image of the subject by compressing the denoised image to the preset target pixel count based on an interpolation algorithm.

Abstract: Methods, devices, and apparatus, including computer programs encoded on a computer storage medium for reconstructing an image are provided. An example method includes: acquiring Computed Tomography (CT) projection data of a subject, determining an image cutoff frequency Fimg according to a CT image matrix size for reconstructing a CT image and an imaging field of view size, obtaining a convolution kernel and a cutoff frequency Fker of the convolution kernel, using the convolution kernel as a reconstruction convolution kernel when Fker<Fimg; adjusting Fker to a product of a preset value k and Fimg and truncating the convolution kernel to obtain a portion of the convolution kernel having a cutoff frequency no more than the adjusted Fker as the reconstruction convolution kernel when Fker?Fimg, and reconstruct the CT image with the CT projection data and the reconstruction convolution kernel by using a convolution back-projection algorithm.

Abstract: A background correction method for CT scan data is provided. A background collection may be performed to collect a first background data set and background data before a CT scan. The CT scan may then be performed to collect one or more CT scan data sets, and status information for collecting each of the CT scan data sets. A second background collection may additionally be performed to collect a second background data set after the CT scan, and status information for collecting the second background data set may also be recorded. The first background data set, the second background data set and corresponding status information may then be used to obtain a background data set for collecting each of the CT scan data sets. The corresponding background data set may be removed from each of the CT scan data set to obtain a background-corrected CT scan data set.

Abstract: Methods, devices and apparatus for reconstructing an image are provided. In one aspect, a method includes: determining an initial angle and a final angle of an X-ray tube and a pitch value when a helical-half-scan is to be performed, obtaining scanning data of each of reconstructing points in a reconstructing position by performing the helical-half-scan on a detected region of a subject based on the determined initial angle, the final angle and the pitch value, determining a respective half-scan-weight and a respective helical weight of each of the reconstructing points in the reconstructing position, obtaining weighted data by performing weighting on the scanning data of each of the reconstructing points with respective the half-scan-weight and the respective helical weight of the reconstructing point, and reconstructing a Computed Tomography (CT) image of the reconstructing position by performing back-projection on the weighted data.

Abstract: A method and apparatus for selecting high and low energy scanning voltages for a dual energy CT scanner are provided. The method may comprise: setting a criterion of selection for selecting high and low energy scanning voltages; generating combinations of high and low energy scanning voltages according to all scanning voltages supported by a dual energy CT scanner, wherein each of the combinations may comprise a high energy scanning voltage and a low energy scanning voltage; and selecting a combination of high and low energy scanning voltages from the generated combinations of high and low energy scanning voltages based on the criterion of selection.

Abstract: A method for correcting a CT scan image is provided. A target image including a target region to be corrected is extracted from an original CT scan image. A target projection range corresponding to the target region is obtained by orthographically projecting the target image, and target projection data within the target projection range is corrected. Noise of the corrected target projection data is adjusted to generate noise-adjusted target projection data to improve noise consistency between target region and the rest of the CT scan image. A corrected CT scan image is reconstructed based on the noise-adjusted target projection data.

Abstract: A method for generating material hardening effect data is provided. Actual X-ray attenuation values of a universal phantom corresponding to different angles at each of channels may be obtained. Equivalent filtration thicknesses corresponding to each of the channels may be determined according to theoretical X-ray attenuation values and the actual X-ray attenuation values corresponding to different angles at each of the channels. Hardening effect data corresponding to a material may be generated according to a predetermined length of the material, a number of sampling points and the equivalent filtration thicknesses corresponding to each of the channels.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for processing a CT (Computed Tomography) image are provided. An example method includes accessing an original CT image that is reconstructed from a first set of raw data and includes windmill artifacts, generating a high-frequency image by processing the original CT image, generating a low-frequency image by processing a plurality of thick images reconstructed from a second set of raw data and combining the plurality of processed thick images, the second set of raw data including the first set of raw data and each of the plurality of thick images including substantially no windmill artifacts, generating an intermediate image by synthesizing the high-frequency image and the low-frequency image, and obtaining a target CT image based on the generated intermediate image.

Abstract: A method for controlling an X-ray dose of a CT scan includes: setting an initial X-ray dose; performing a first CT scan with the initial X-ray dose to obtain an initial scan image; setting a region of interest (ROI) in the initial scan image; calculating a subsequent X-Ray dose with image values of the ROI in the initial scan image; perform an additional CT scan with the calculated subsequent X-Ray dose to obtain an average image; before receiving an end instruction, repeating the following operations: recalculating a subsequent X-Ray dose with image values of the ROI in the average image and performing an additional CT scan with the calculated subsequent X-Ray dose to obtain a new average image; and saving the average image when receiving the end instruction.

Abstract: A method for reconstructing a CT scan image, comprising: performing a first scan to acquire a first projection data, wherein the first scan is a scan that a subject is covered by a low dose X-ray beam in an axial plane; performing a second scan to acquire a second projection data, wherein the second scan is a scan that a target portion of the subject is covered by a high dose X-ray beam in the axial plane; determining a data filling point in the second projection data, wherein the data filling point is located in a truncated region; and filling the data filling point in the second projection data with a data from the first projection data which corresponds to the data filling point; and reconstructing a second scan image based on the filled second projection data.

Abstract: Methods and devices for reconstructing dual-energy CT images are provided. In one aspect, CT scan is performed with a high energy and a low energy periodical and alternatively changed on a scanning target, reconstruction data for a high-energy image of a current reconstruction position is obtained based on whether a circle of high-energy scan closest to the current reconstruction position of the scanning target is a full circle of scan, the high-energy image of the current reconstruction position is reconstructed according to the reconstruction data of the high-energy image; reconstruction data for a low-energy image of the current reconstruction position is obtained based on whether a circle of high-energy scan closest to the current reconstruction position of the scanning target is the full circle of scan, the low-energy image of the current reconstruction position is reconstructed according to the reconstruction data of the low-energy image.

Abstract: A method and system for CT image correction are provided. Contour data of a scanned subject can be obtained, and a shape image of the scanned subject can be reconstructed according to the contour data, wherein the contour data of the scanned subject can be obtained by scanning the scanned subject through a piece of visual equipment. Original CT projection data of the scanned subject can be obtained, and a CT image can be reconstructed according to the original CT projection data. For determining a supervision field image, image matching can be performed between the shape image and the CT image of the scanned subject. Supervision field projection data can be obtained, and the supervision field projection data can be used to correct the CT image.

Abstract: Methods of reconstructing a CT image and CT devices are provided in examples of the present disclosure. In one aspect, scanning parameters for a CT device is obtained to perform a scan on a subject, a target reference detector is determined from the reference detectors according to the scanning parameters; the scan is performed on the subject according to the scanning parameters to obtain detection data outputted by the detector and reference detection data outputted by the target reference detector; energy data of the original X-rays emitted by the bulb tube with the scanning parameters is determined according to the reference detection data outputted by the target reference detector; the detection data outputted by the detector is corrected based on the energy data of the original X-rays to obtain scanning data; and the CT image of the subject is reconstructed by performing image reconstruction based on the scanning data.

Abstract: The present disclosure provides a sampling method and sampling apparatus of a scanning device. In at least one example, the sampling method comprises acquiring a ray attenuation variation at each of a plurality of scanning angles of the scanning device, determining a corrected sampling interval at each of the scanning angles of the scanning device by adjusting an initial sampling interval at each of the scanning angles of the scanning device according to the ray attenuation variation at each of scanning angles, and performing actual sampling according to the corrected sampling interval at each of the scanning angles of the scanning device.

Abstract: A method of selecting a slice configuration of a medical imaging apparatus is provided. The method includes: picking out two or more candidate slice configurations from available slice configurations of the medical imaging apparatus; determining a scan dose corresponding to each of the two or more candidate slice configurations; and selecting a candidate slice configuration corresponding to a minimum scan dose as a target slice configuration, where the target slice configuration is used for a current scan protocol.

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: Methods, devices, and apparatus, including computer programs encoded on a computer storage medium for reconstructing an image are provided. An example method includes: acquiring Computed Tomography (CT) projection data of a subject, determining an image cutoff frequency Fimg according to a CT image matrix size for reconstructing a CT image and an imaging field of view size, obtaining a convolution kernel and a cutoff frequency Fker of the convolution kernel, using the convolution kernel as a reconstruction convolution kernel when Fker<Fimg; adjusting Fker to a product of a preset value k and Fimg and truncating the convolution kernel to obtain a portion of the convolution kernel having a cutoff frequency no more than the adjusted Fker as the reconstruction convolution kernel when Fker?Fimg, and reconstruct the CT image with the CT projection data and the reconstruction convolution kernel by using a convolution back-projection algorithm.

Abstract: Provided is a method of selecting a slice configuration of a medical imaging apparatus. According to an example, an expected scanning time for scanning a region of a scanning length by the medical imaging apparatus with each of candidate slice configurations may be determined, and one or more first slice configurations are selected from the candidate slice configurations in a way that the scanning time of each of the first slice configurations is less than a preset threshold. An expected scanning length and an expected redundant scanning dose for scanning the region by the medical imaging apparatus with each of the first slice configurations may be determined. In this way, for scanning the region by the medical imaging apparatus, a target slice configuration may be selected from the first slice configurations according to the expected redundant scanning dose.

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.