33 results about "For Attenuation Correction" patented technology

A method of producing a nuclear medicine image of a subject comprising the steps of acquiring nuclear image data suitable to produce a nuclear tomographic image, the data being acquired by at least one gamma camera head (12, 14) rotating about the subject at an average first rate, acquiring x-ray imaging data suitable to produce an x-ray tomographic image for attenuation correction of the gamma camera image, the data being acquired by an array of detectors (20) irradiated by an x-ray source (18) rotating around the subject at an average second rate which is within a factor of 10 of the first rate, and reconstructing an attenuation corrected nuclear medicine image utilizing the nuclear imaging data and x-ray imaging data.

Methods and systems for imaging a patient are provided. The method includes scanning a patient and acquiring a plurality of frames of cine computed tomography (CT) images during one complete respiratory cycle. In one embodiment, a method is provided that includes selecting an organ of interest in the cine CT data and selecting a value for each pixel in the organ of interest that represents the maximum density measurement. An attenuation corrected positron emission tomography (PET) image is constructed based on the maximization of the pixel intensity of the organ of interest in the CT attenuation correction map. Incorrect attenuation correction values for PET images can be avoided by utilizing the CT attenuation correction map.

Methods and systems for imaging a patient are provided. The method includes scanning a patient and acquiring a plurality of frames of cine computed tomography (CT) images during one complete respiratory cycle. In one embodiment, a method is provided that includes selecting a value for each pixel that represents the maximum density measurement for the pixel throughout the cine acquisition. In one embodiment, an attenuation correction image of a volume of interest is constructed by weighting a combination of the maximum pixel intensity value and an average pixel intensity value. Undesirable motion artifacts can be removed from positron emission tomography (PET) images by utilizing the CT attenuation correction image.

Methods and systems for imaging a patient are provided. The method includes scanning a patient and acquiring a plurality of frames of cine computed tomography (CT) images during one complete respiratory cycle. In one embodiment, a method is provided that includes selecting an organ of interest in the cine CT data and selecting a value for each pixel in the organ of interest that represents the maximum density measurement. An attenuation corrected positron emission tomography (PET) image is constructed based on the maximization of the pixel intensity of the organ of interest in the CT attenuation correction map. Incorrect attenuation correction values for PET images can be avoided by utilizing the CT attenuation correction map.

The present invention relates to systems and methods for attenuation correction to improve reconstructed image quality and quantitative accuracy and reduce radiation dose in emission computed tomography. In one embodiment, the present invention provides an interpolated average CT (IACT) method and breathing control devices.

Emission contamination data are collected in a shifted mock scan simultaneous with the collection of transmission data during a transmission scan of a patient with a collimated gamma point source, the transmission data are corrected with the emission contamination data, and the corrected transmission data are used for attenuation correction of emission data for reconstruction of an emission image of the patient. In a preferred implementation, when the point source is at a particular axial location and illuminates an axial beamwidth of “Fz” over the gamma detector, emission contamination data are collected from the gamma detector over an axial separated region “Fz′” having about the same axial extent but axially displaced by about half of the axial field of view (FOV).

The invention relates to MR scan selection for PET attenuation correction. A method of attenuation correction for a positron emission tomography (PET) system (52) includes: obtaining PET scan data representative of a volume scanned by the PET system (52); obtaining a plurality of magnetic resonance (MR) scan data sets representative of the volume, each MR scan data set being acquired in a respective time period during acquisition of the PET scan data by the PET system; detecting motion of the volume that occurred during the acquisition of the PET scan data based on an assessment of the plurality of MR scan data sets, the PET scan data, or the plurality of MR scan data sets and the PET scan data; determining attenuation correction data from the plurality of MR scan data sets based on the detected motion for alignment of the attenuation correction data and the PET scan data; and correcting the PET scan data with the attenuation correction data.

Embodiments of the present invention provide the use of average CT (ACT) to match the temporal resolution of CT and PET to enhance PET imaging and evaluated tumor quantification with HCT and ACT. For example, an embodiment of a method of enhanced PET imaging on a PET / CT scanner includes generating an average CT scan responsive to 4D CT emission image data to thereby correct attenuation in PET emission image data. Another embodiment of a method of attenuation correction in a PET / CT scan includes averaging a plurality of consecutive low dose CT images of approximately one breathing cycle to thereby obtain an average CT.

For patient transmission data acquired simultaneously with patient emission data, blank transmission data are acquired in the absence of the patient emission and therefore under count rate conditions different from the count rate conditions of the patient transmission data. To prevent the different count rate conditions from causing artifacts in reconstructed tomographic images, a correction is made for spatially varying count rate effects on the attenuation correction. For example, the blank scan data are adjusted according to the count rate at which the patient emission data are acquired, and the adjusted blank scan data and the patient transmission data are used for attenuation correction of the patient emission data used for reconstructing a tomographic image.

The invention relates to an acquisition method of a PET image attenuation coefficient and a method and system for attenuation correction. Under the circumstance based on regional CT scanning, the CT value of a first sub region, for example, a tone tissue, can be objectively acquired by means of a mapping relationship between the CT value of the CT scanning region and the pixel value of a PET scanning region, and a first attenuation coefficient of the first sub region is quantificationally acquired according to the CT value of the first sub region. Compared with direct assignment on the attenuation coefficient on the first sub region of the bone tissue after image cutting, the result is more accurate and reliable.

A method for attenuation correction of a phantom image in a PET imaging system includes obtaining raw scan data of a scanned phantom, a non attenuation corrected template image of a stock phantom of like type to the scanned phantom, and an attenuation map of the stock phantom. The method further includes generating a non-attenuation corrected raw image of the scanned phantom based on the raw scan data, registering the template image and attenuation map to the raw image through a rigid image transform, and applying the registered attenuation map to the raw scan data to enable reconstruction of an attenuation corrected final image.

The invention discloses a computed tomography (CT) image generation method used for attenuation correction of positron emission tomography (PET) images. According to the method, CT images and PET images at the moment T1 and PET images at the moment T2 are acquired and input into a trained deep learning network, CT images at the moment T2 are acquired, the CT images can be applied to the attenuation correction of the PET images, and therefore, relatively accurate PETAC (attenuation correction) images can be obtained. According to the method, the dosage of X-rays received by a patient in the whole image acquisition stage can be reduced, and physiological and psychological pressure of the patient is relieved. Besides, the later image acquisition only needs PET imaging equipment, PET / CT equipment is not needed, cost of imaging resource distribution can be reduced, and the imaging expense of the whole stage is reduced.

In a method for attenuation correction of emission tomography scan data acquired from an examination object in a combined magnetic resonance emission tomography apparatus, wherein an interference object is situated in the examination region, which causes a magnetic interference field during combined magnetic resonance emission tomography imaging, magnetic resonance scan data of the examination object are acquired by executing a magnetic resonance sequence designed to at least partially compensate inference due to the magnetic interference field. Emission tomography scan data are acquired and an attenuation map is generated using the acquired magnetic resonance scan data. Attenuation correction of the emission tomography scan data is implemented using the generated attenuation map.

Emission contamination data are collected in a shifted mock scan simultaneous with the collection of transmission data during a transmission scan of a patient with a collimated gamma point source, the transmission data are corrected with the emission contamination data, and the corrected transmission data are used for attenuation correction of emission data for reconstruction of an emission image of the patient. In a preferred implementation, when the point source is at a particular axial location and illuminates an axial beamwidth of “Fz” over the gamma detector, emission contamination data are collected from the gamma detector over an axial separated region “Fz′” having about the same axial extent but axially displaced by about half of the axial field of view (FOV).

A method and apparatus of image reconstruction attenuation correction in PET or SPECT cardiac imaging is provided. A volumetric attenuation imaging scan by an X-ray source may be used to generate a gamma ray attenuation map. The volumetric attenuation imaging scan may be randomized, and may be performed while the imaged subject is breathing.

A method for attenuation correction of a plurality of time-gated PET images of a moving structure includes establishing an ACF matrix, based on a baseline MR image of the structure; developing a plurality of image transforms, each of the image transforms registering the baseline MR image to a respective cine MR image of the moving structure; applying each of the image transforms to the ACF matrix to generate a corresponding cine ACF matrix; time-correlating each of the cine MR images, and its corresponding cine ACF matrix, to one of the plurality of time-gated PET data sets; and producing from each of the time-gated PET data sets an attenuation-corrected time-gated PET image.

A positioning method of a CT image for PET attenuation correction comprises the following steps: (1) acquiring Dicom image data scanned by a CT, and determining a maximum inspection region C1MAX to C2MAX from the Dicom image data; 2) determining that a range of a PET image to be corrected in the Z-axis is P1 to P2, and determining a relative difference delta between positions of the CT and a PET examining table to determine that an initial value range of a target CT image in the Z-axis is P1-delta to P2-delta, (3) traversing the Dicom data of the CT image, determining index values CIndex1 to CIndex2 corresponding to the Z-axis position of the target CT image at the P1-delta to the P2-delta, wherein the CIndex1 is a maximum value index where the Z-axis position of the target CT image is less than a Z-axis minimum value of the PET image, the CIndex2 is a minimum value index where the Z-axis position of the target CT image is greater than the Z-axis minimum value of the PET image, and theCT image between the CIndex1 and the CIndex2 is a value range of the target CT image. The positioning method can effectively determine the number of layers of the target CT image corresponding to thePET image to be corrected, and is used for attenuation correction of the PET image to be corrected.

Systems and methods for attenuation correction are disclosed. The system includes a coil module (430, 600, 800), which includes a flexible coil (510, 610, 810) and a supporter (520, 620, 820). The supporter (520, 620, 820) may be configured to hold the flexible coil (510, 610, 810). The flexible coil (510, 610, 810) may be deformed to form a receiving space.

The invention belongs to the technical field of image imaging, and particularly relates to an image attenuation correction method and application thereof. At present, an image obtained by a method forproviding anatomical information for attenuation correction by computer tomography is not clear. For the synthesis from an NAC-PET image to an AC-PET image, self-correcting convolution can improve the extraction of the NAC-PET image content information by a generator and increase receptive field of convolutional layer (the receptive field being size of region mapped by pixel points on feature mapoutput by each layer of convolutional neural network (CNN) on original input image); and after the receptive field is increased, the pixel points on the feature map subjected to convolution extraction can better reflect information in the original image, and attenuation correction can be better carried out on a non-attenuation correction image (NAC-PET).

The present application relates to systems and methods for attenuation correction. The system includes a coil module (430, 600, 800) including a flexible coil (510, 610, 810) and a support (520, 620, 820). The support (520, 620, 820) may be configured to support the flexible coil (510, 610, 810). The flexible coil (510, 610, 810) is deformable to form a receiving space.

A method for attenuation correcting a PET image of a target includes locating a radiopaque structure by MRI scan of the target; fitting a model of the radiopaque structure to the MRI scan image; and correcting attenuation of the PET image based on the fitted model.

The present invention relates to MR scan selection for PET attenuation correction. A method for attenuation correction for a positron emission tomography (PET) system (52) comprising: obtaining PET scan data representing a volume scanned by the PET system (52); obtaining a plurality of magnetic resonance (MR) scan data sets representing the volume, each MR scan data set being acquired in a corresponding time period during acquisition of the PET scan data by the PET system (52); Detecting volumetric motion that occurs during acquisition of the PET scan data; determining attenuation correction data from the plurality of MR scan data sets based on the detected motion for alignment of the attenuation correction data with the PET scan data; and correcting the PET scan data using the attenuation correction data.

The invention discloses a correction information acquisition method for performing attenuation correction on PET images of breathing or heart. The method includes: acquiring PET detection data with time-of-flight information and gating signals reflecting periodic movement of breathing or heart; The PET detection data of a cycle is divided into B phases, the PET detection data of the same phase in all cycles are combined, the sum of each phase is obtained, and the transformation matrix between any phase in the B phases and the basic phase is obtained, and the transformation is established. The first relationship between the matrix and the estimated value of the PET activity distribution corresponding to each phase; obtain the PET activity distribution estimation model corresponding to the basic phase; iteratively process the PET activity distribution estimation model to obtain The PET activity distribution corresponding to the basal phase. The foregoing can solve the problem of attenuation artifacts in PET image reconstruction in the prior art, and can ensure accurate quantification of attenuation correction.

A PET-MRI system for imaging an object is provided. The PET-MRI system includes a magnetic resonance imaging sub-system, a positron emission tomography sub-system, an optical sensor, and a data processing controller. The magnetic resonance imaging sub-system includes a surface coil that acquires magnetic resonance signals from the object. The positron emission tomography sub-system acquires PET emissions from the object. The optical sensor detects at least one of a spatial location and a shape of the surface coil. The data processing controller communicates with the magnetic resonance imaging sub-system, the positron emission tomography sub-system, and the optical sensor, and utilizes at least one of the detected spatial location and the detected shape of the surface coil to correct the acquired PET emissions for attenuation.

A method and apparatus of image reconstruction attenuation correction in PET or SPECT cardiac imaging is provided. A volumetric attenuation imaging scan by an X-ray source may be used to generate a gamma ray attenuation map. The volumetric attenuation imaging scan may be randomized, and may be performed while the imaged subject is breathing.

The invention discloses a single-bed PET delayed imaging method without accompanying CT radiation. First, an image reconstruction network capable of converting a PET BP image into a pseudo PET image closer to a real PET image is used to obtain a normal scan and a delayed scan. The PET BP image is converted into a Pseudo PET image, and then a CT image generation network is used to input the normal scan Pseudo PET image and CT image, as well as the delayed scan Pseudo PET image, and output the deformation field between the normal scan and the delayed scan and The CT image at the time of the delayed scan, which is finally used for attenuation correction in the reconstruction of the delayed scan PET image, obtains a PET image with accurate SUV quantification and is used for tumor detection. The method of the invention can eliminate the CT radiation received by the patient in delayed scanning, reduce the physiological and psychological pressure of the patient, and promote the application of delayed PET imaging.

The invention relates to a PET image attenuation coefficient acquisition method, attenuation correction method and system. In the case of segmental CT scanning, the CT value of the first sub-region such as bone tissue can be obtained objectively through the mapping relationship between the CT value of the CT scanning area and the pixel value of the PET scanning area, and according to the first sub-region Quantitatively obtaining the first attenuation coefficient of the first sub-region from the CT value of the region is more accurate and reliable than directly assigning the attenuation coefficient to the first sub-region such as bone tissue after image segmentation.

In a method for attenuation correction of emission tomography scan data acquired from an examination object in a combined magnetic resonance emission tomography apparatus, wherein an interference object is situated in the examination region, which causes a magnetic interference field during combined magnetic resonance emission tomography imaging, magnetic resonance scan data of the examination object are acquired by executing a magnetic resonance sequence designed to at least partially compensate inference due to the magnetic interference field. Emission tomography scan data are acquired and an attenuation map is generated using the acquired magnetic resonance scan data. Attenuation correction of the emission tomography scan data is implemented using the generated attenuation map.

The invention relates to an attenuation correction method for positron emission tomography data, and a combined positron emission tomography and magnetic resonance tomography system. Various embodiments relate to methods of attenuation correction of positron emission tomography (PET) data based on magnetic resonance tomography (MRT) data. The method also includes determining other data indicative of a cycle period of the patient's physiological observables, and matching the PET data to the MRT data based on these other data.