Abstract: A medical imaging system includes a view transformation component (210) and a segment combiner (212). The transformation component (210) transforms projection data in each view of a plurality of individual segments, which each includes at least one view. The transformed projection data for substantially similar views across the plurality of individual segments have a common radius of rotation. The segment combiner (212) combines the transformed projection data to produce a single data set that includes the transformed projection data for each of the views of each of the plurality of individual segments.

Abstract: A positron emission tomography (PET) imaging system (10) includes a singles unit (24), a delay unit (26), a scaling unit (28), and a reconstruction unit (30). The singles unit (24) is configured to generate a correction sinogram of random coincidences defined by a coincidence time window tw and a time period t based on rij=2 t si sj where rij is an estimate of the random coincidences in the time period t between singles at detector locations si and sj. The delay unit (26) is configured to determine delay coincidences in the time period t defined by a delay coincidence time window of a paired coincidences including tw to 2 tw. The scaling unit (28) is configured to scale the correction sinogram of random coincidences based on the delay coincidences. The reconstruction unit (30) is configured to iteratively reconstruct one or more images based on the scaled random sinogram and a prompt sinogram for the time period t.

Abstract: A system (10) and a method (100) iteratively reconstruct an image of a target volume of a subject. In each iteration of a plurality of iterations, an estimate image of the target volume (54) is forward projected (58) and compared (62) to received event data (44) to determine a discrepancy (64). The discrepancy (64) is back projected (66) and the back projection (68) updates (70) the estimate image (54). In at least one iteration, the estimate image (54) is filtered (52) in the image domain prior to being back projected.

Abstract: 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.

Abstract: A nuclear camera acquires projections which are iteratively reconstructed by a reconstruction processor into an motion-artifacted image and stored in an image memory. The motion-artifacted image is forward-projected by a forward-projector to create forward-projections which are compensated for image degrading factors, such as resolution recovery, scatter and attenuation, and are compared with the acquired projections by a comparing unit to generate a motion-correction. A motion compensator operates on the acquired projections with the motion-correction to generate a motion-corrected projection data set in which each of the projections is in a common motion state. The motion-corrected projections are reconstructed into a motion-corrected image.

Abstract: An imaging method and corresponding system (10) account for cascade gammas. Event data describing detected gamma rays emitted from a target volume of a subject are received. The detected gamma rays include cascade gammas emitted from a radionuclide within the target volume. Cascade and annihilation gamma emissions from the target volume and coincidence detection of the imaging system (10) are simulated using a Monte Carlo (MC) simulation technique to generate a cascade dataset comprised of annihilation coincidence events and cascade coincidence events. The event data is reconstructed into an image representation of the target volume with correction of cascade coincidence using the relationship between the annihilation coincidence events and the cascade coincidence events in the cascade data set.

Abstract: An apparatus comprises: an imaging system (10) configured to acquire emission data from a cyclically varying element; a monitoring instrument (20, 22) configured to measure the cyclical varying of the cyclically varying element; and an electronic device (40) configured to locate an image feature corresponding to the cyclically varying element in the acquired emission data based on correlation of time variation of the emission data with the cyclical varying of the cyclically varying element measured by the monitoring instrument. The located image feature may be verified by: thresholding a projection image generated from the emission data to generate a mask image; identifying in the mask image one of (i) a hollow circular feature, (ii) a hollow oval feature, (iii) a circular cavity feature, and (iv) an oval cavity feature; and verifying the located image feature based on whether the identifying operation is successful.

Abstract: When imaging a compact structure, such as a calcium deposit in a patient's heart, a slow scan (e.g., less than approximately 6 rpm) CT data acquisition is performed, wherein data is continuously but sparsely acquired during around a 360° revolution around the patient. Arc segments are defined that equate to one heart cycle (e.g., heartbeat) given the patient's heart rate and the speed of the CT gantry. Electrocardiogram signal data is used to identify sets of acquired projection data that correspond to each of a plurality of heart cycle phases during which the heart is relatively still. A sparse reconstruction algorithm is executed on the identified sets of sparse projection data to generate images for each heart cycle phase from the scan data acquired for that phase across all heart cycles.

Abstract: A gantry free nuclear imaging system (10) images a region of interest (ROI) (16). The system (10) includes one or more radiation detectors (20) generating radiation data indicating the location of gamma photon strikes. The system includes a reconfigurable frame (22) positioning the radiation detectors (20) at fixed viewing angles of the ROI (16) and at least one processor (44, 48). The processor (44, 48) receives the radiation data from the radiation detectors (20) and reconstructs an image of the ROI (16) from the received radiation data.

Abstract: An image processing apparatus includes a scatter simulation processor which processes measured sinograms generated from imaging data acquired for an imaging subject by an imaging apparatus to produce a scatter sinogram that represents a shape of scatter contribution. A scatter scaling processor utilizes a Monte Carlo simulation to determine a scatter fraction and scales the scatter sinogram to generate a scaled scatter sinogram that matches the scatter contribution in the measured sinogram. A reconstruction processor reconstructs the imaging data into an image representation using the scaled scatter sinogram for scatter correction.

Abstract: A medical imaging system includes a data store (16) of re-construction procedures, a selector (24), a reconstructor (14), a fuser (28), and a display (22). The data store (16) of reconstruction procedures identifies a plurality of reconstruction procedures. The selector (24) selects at least two reconstruction procedures from the data store of reconstruction procedures based on a received input, each reconstruction procedure optimized for one or more image characteristics. The reconstructor (14) concurrently performs the selected at least two reconstruction procedures, each reconstruction procedure generates at least one image (26) from the at least one data store of imaging data (12). The fuser (28) fuses the at least two generated medical images to create a medical diagnostic image which includes characteristics from each generated image (26). The display (22) displays the medical diagnostic image.

Abstract: A whole body SPECT system (10) includes a patient support (14) and a static gantry (12) which includes a plurality of rings (40a,40b,40c) of radiation detectors (42). The patient support (14) supports a patient and moves the patient in an axial direction (18) through the static gantry (12). One or more processors (20,24,32) connected to the plurality of detectors records strikes of gamma photons in the radiation detectors (42) and reconstruct the recorded strikes of the gamma photons into a whole body image.

Abstract: A gantry free nuclear imaging system (10) images a region of interest (ROI) (16). The system (10) includes one or more radiation detectors (20) generating radiation data indicating the location of gamma photon strikes. The system includes a reconfigurable frame (22) positioning the radiation detectors (20) at fixed viewing angles of the ROI (16) and at least one processor (44, 48). The processor (44, 48) receives the radiation data from the radiation detectors (20) and reconstructs an image of the ROI (16) from the received radiation data.

Abstract: A nuclear camera acquires projections which are iteratively reconstructed by a reconstruction processor into an motion-artifacted image and stored in an image memory. The motion-artifacted image is forward-projected by a forward-projector to create forward-projections which are compensated for image degrading factors, such as resolution recovery, scatter and attenuation, and are compared with the acquired projections by a comparing unit to generate a motion-correction. A motion compensator operates on the acquired projections with the motion-correction to generate a motion-corrected projection data set in which each of the projections is in a common motion state. The motion-corrected projections are reconstructed into a motion-corrected image.

Abstract: Hybrid dual-modality image processing systems and methods are disclosed. For example, an image processing system includes a computer for processing SPECT tomographic projection data and a CT volume image. The computer derives a SPECT transverse volume image from the projection data and registers the SPECT transverse volume image with the CT volume image to obtain an attenuation map and registration information. The computer uses the attenuation map and the registration information to derive a SPECT transverse volume image with attenuation correction. The computer uses the registration information to derive a SPECT transverse volume image without attenuation correction. The SPECT transverse volume images, with and without attenuation correction, are derived at or near the same time, using the same registration information. The registration information is stored in, carried by, or otherwise communicated through the attenuation map for subsequent processing of the SPECT transverse volume images.

Abstract: A nuclear imaging system (110) includes a radiation detector (112) having a distance dependent spatial resolution. A reconstructor (124) reconstructs projections acquired by the detector to generate image data. The reconstructor (124) applies a distance dependent projection filter (134) so as to reduce angular dependent resolution variations in the image space data.

Abstract: An apparatus comprises: an imaging system (10) configured to acquire emission data from a cyclically varying element; a monitoring instrument (20, 22) configured to measure the cyclical varying of the cyclically varying element; and an electronic device (40) configured to locate an image feature corresponding to the cyclically varying element in the acquired emission data based on correlation of time variation of the emission data with the cyclical varying of the cyclically varying element measured by the monitoring instrument.

Abstract: When imaging a compact structure, such as a calcium deposit in a patient's heart, a slow scan (e.g., less than approximately 6 rpm) CT data acquisition is performed, wherein data is continuously but sparsely acquired during around a 360° revolution around the patient. Arc segments are defined that equate to one heart cycle (e.g., heartbeat) given the patient's heart rate and the speed of the CT gantry. Electrocardiogram signal data is used to identify sets of acquired projection data that correspond to each of a plurality of heart cycle phases during which the heart is relatively still. A sparse reconstruction algorithm is executed on the identified sets of sparse projection data to generate images for each heart cycle phase from the scan data acquired for that phase across all heart cycles.

Abstract: An imaging system (10) comprises at least one radiation detector (20) disposed adjacent a subject receiving aperture (18) to detect radiation from a subject, receive the radiation and generate measured data. An image processor (38) iteratively reconstructs the detected radiation into image representations, in each reconstruction iteration the image processor (38) applies noise reduction algorithms to at least a difference between the measured data and a portion of a previous iteration image representation.

Abstract: Hybrid dual-modality image processing systems and methods are disclosed. For example, an image processing system includes a computer for processing SPECT tomographic projection data and a CT volume image. The computer derives a SPECT transverse volume image from the projection data and registers the SPECT transverse volume image with the CT volume image to obtain an attenuation map and registration information. The computer uses the attenuation map and the registration information to derive a SPECT transverse volume image with attenuation correction. The computer uses the registration information to derive a SPECT transverse volume image without attenuation correction. The SPECT transverse volume images, with and without attenuation correction, are derived at or near the same time, using the same registration information. The registration information is stored in, carried by, or otherwise communicated through the attenuation map for subsequent processing of the SPECT transverse volume images.