Abstract: A multi-modality imaging system allows for selectable photoelectric effect and/or Compton effect detection. The camera or detector is a module with a catcher detector. Depending on the use or design, a scatter detector and/or a coded physical aperture are positioned in front of the catcher detector relative to the patient space. For low energies, emissions passing through the scatter detector continue through the coded aperture to be detected by the catcher detector using the photoelectric effect. Alternatively, the scatter detector is not provided. For higher energies, some emissions scatter at the scatter detector, and resulting emissions from the scattering pass by or through the coded aperture to be detected at the catcher detector for detection using the Compton effect. Alternatively, the coded aperture is not provided. The same module may be used to detect using both the photoelectric and Compton effects where both the scatter detector and coded aperture are provided with the catcher detector.

Abstract: For calibration in medical emission tomography, the dosimeter and/or detector is calibrated in the field, such as at the clinic or other patient scanning location. To allow for a fewer number of calibration sources used in calibrating and/or assist in calibration for multispectral emission tomography, a calibration source includes multiple isotopes and/or a proxy source or isotope is used instead of the same isotope used in factory calibration.

Abstract: A physics-based network model is trained to learn weights such as trapping, detrapping, and/or transport of holes and/or electrons, as well as voltage distribution on a voxel-by-voxel basis throughout a solid-state detector model. The physics-based network may be used to estimate material property variation throughout the voxels. To reduce the number of experimental setups and information needed to train the models, the models may be trained using more easily acquired ground truth. Just the electrode signals or just the free charge data is used to train the model to characterize the solid-state detector. With this reduced data, the detector may be characterized using equivalency, such as combining multiple trapping centers to an equivalent trapping center. Regularization may be used in the loss calculation, such as where just the electrode signals are used, to deal with the reduced data available as ground truth.

Abstract: A framework for characterization of a collimator. In accordance with one aspect, first and second sides of the collimator are photographed to generate first and second image data. An optical characterization map (OCM) may be generated based on the first and second image data, wherein the optical characterization map characterizes the individual channels of the collimator. Quality assessment or image reconstruction may then be performed based on the OCM.

Abstract: For calibration in medical emission tomography, the dosimeter and/or detector is calibrated in the field, such as at the clinic or other patient scanning location. To allow for a fewer number of calibration sources used in calibrating and/or assist in calibration for multispectral emission tomography, a calibration source includes multiple isotopes and/or a proxy source or isotope is used instead of the same isotope used in factory calibration.

Abstract: For partial volume correction, the partial volume effect is simulated using patient-specific segmentation. An organ or other object of the patient is segmented using anatomical imaging. For simulation, the locations of the patient-specific object or objects are sub-divided, creating artificial boundaries in the object. A test activity is assigned to each sub-division and forward projected. The difference of the forward projected activity to the test activity provides a location-by-location partial volume correction map. This correction map is used in reconstruction from the measured emissions, resulting in more accurate activity estimation with less partial volume effect.

Abstract: A system and method include training of an artificial neural network to generate an output three-dimensional image volume based on input two-dimensional projection images, the training based on a plurality of subsets of two-dimensional projection images of each of a plurality of sets of two-dimensional projection images and associated ones of three-dimensional image volumes reconstructed from each of the plurality of sets of two-dimensional projection images.

Abstract: A system and method includes acquisition of a plurality of images, each of the plurality of images representing radiotracer concentration in a respective volume at a respective time period, and training of a neural network, based on the plurality of images, to output data indicative of radiation dose associated with a first volume over a first time period based on a first image representing radiotracer concentration in the first volume over a second time period, the second time period being shorter than the first time period.

Abstract: A system and method include an array of sensors electrically coupled to a material capable of converting a gamma ray to electrical charge, where distances between a center of a first sensor and centers of each sensor immediately-adjacent to the first sensor are substantially equal. Signals are collected from each sensor immediately-adjacent to the first sensor, and one of a plurality of logical sub-pixels of the first sensor is determined based on the signals collected from each sensor immediately-adjacent to the first sensor.

Abstract: A detector used for tomography imaging is mobile, allowing the detector to move about an object (e.g., patient to be imaged). A swarm of such detectors, such as a swarm of drones with detectors, may be used for tomography imaging. The trajectory or trajectories of the mobile detectors may account for the pose and/or movement of the object being imaged. The trajectory or trajectories may be based, in part, on the sampling for desired tomography. An image of an internal region of the object is reconstructed from detected signals of the mobile detectors using tomography.

Abstract: A system and method includes determination of a region of interest of an imaging subject, generation of a first linear attenuation coefficient map of the imaging subject, the first linear attenuation coefficient map generated to associate voxels of the region of interest of the imaging subject with greater linear attenuation coefficients than voxels of other regions of the imaging subject, attenuation-correction of a plurality of tomographic frames of the imaging subject based on the first linear attenuation coefficient map to generate a second plurality of tomographic frames, and determination of tomographic inconsistency of the second plurality of tomographic frames.

Abstract: A Compton camera for medical imaging is divided into segments with each segment including part of the scatter detector, part of the catcher detector, and part of the electronics. The different segments may be positioned together to form the Compton camera arcing around part of the patient space. By using segments, any number of segments may be used to fit with a multi-modality imaging system.

Abstract: A framework for quality-driven image processing. In accordance with one aspect, image data and anatomical data of a region of interest are received. Zonal information is generated based on the anatomical data. Image processing is performed based on the image data to generate an intermediate image. One or more image quality metrics may then be determined for the intermediate image data using the zonal information. A processing action may be performed based on the one or more image quality metrics to generate a final image.

Abstract: This application relates to methods, systems, and apparatus for replacing native heart valves with prosthetic heart valves and treating valvular insufficiency. In a representative embodiment, a support frame configured to be implanted in a heart valve comprises a main body formed by formed by a plurality of inner members forming an inner clover and a plurality of outer members forming an outer clover. The support frame can include gaps located between inner members of the plurality of inner members and outer members of the plurality of outer members. The inner clover can be radially inside the outer clover, and the outer clover can have larger dimensions than the inner clover. The support frames herein can be radially expandable and collapsible.

Abstract: For gamma ray detection, 3D tiling is made possible by modules that include a gamma ray detector with at least some electronics extending away from the detector as a side wall, leaving an air or low attenuation gap behind the gamma ray detector. The modules may be stacked to form arrays of any shape in 3D, including stacking to form a Compton detector with a scatter detector separated from the catcher detector by the low attenuation gap where the electronics form at least one side wall between the detectors. The modules may be stacked so that the detectors from the different modules are in different planes and/or not part of a same surface (e.g., same surface provided with just 1D or 2D tiling).

Abstract: For calibration of internal dose in nuclear imaging, the dose model used for estimating internal dose in a patient is calibrated. One or more values of the dose model (e.g., a physics simulation, dose kernels, or a transport model) are set based on measured dose. The dose may be measured relative to specific tissues and/or isotopes, providing for tracer and tissue specific calibration. For example, dose from the tracer to be injected into the patient is estimated from emissions as well as measured by a dosimeter in a tissue mimicking tissue mimicking object. These doses are used to calibrate the dose model, which calibrated dose model is then used to determine internal dose for the patient.

Abstract: For dosimetry, a miniaturized nuclear imaging system with a solid-state detector is used to determine the activity and/or injected dose for a radiopharmaceutical. By being sized to scan the syringe or vial, the injected dose may be determined using the solid-state detector with greater accuracy than current dose calibrators and with less frequent use of a calibrated or standardized source. This miniaturized nuclear imaging system reconstructs activity in a same way as the nuclear imaging system scanning a patient, so may be used to calibrate the dose model. A tissue mimicking object with a solid-state dosimeter measures dose from the radiopharmaceutical, which dose is used to calibrate the dose model.

Abstract: This application relates to methods, systems, and apparatus for replacing native heart valves with prosthetic heart valves and treating valvular insufficiency. In some implementations, a heart valve leaflet clipping mechanism includes a delivery apparatus and clipping arms. The clipping arms are coupled to the delivery apparatus. The clipping arms are movable between an open position and a closed position. The two clipping arms are biased to the closed position. The delivery apparatus is configured to hold the clipping arms in the open position. The delivery apparatus is configured to allow the clipping arms to move to the closed position to engage native heart valve leaflet tissue.

Abstract: A system and method includes determination of a region of interest of an imaging subject, generation of a first linear attenuation coefficient map of the imaging subject, the first linear attenuation coefficient map generated to associate voxels of the region of interest of the imaging subject with greater linear attenuation coefficients than voxels of other regions of the imaging subject, attenuation-correction of a plurality of tomographic frames of the imaging subject based on the first linear attenuation coefficient map to generate a second plurality of tomographic frames, and determination of tomographic inconsistency of the second plurality of tomographic frames.

Abstract: This application relates to methods, systems, and apparatus for replacing native heart valves with prosthetic heart valves and treating valvular insufficiency. In a representative embodiment, a support frame configured to be implanted in a heart valve comprises a main body formed by formed by a plurality of inner members forming an inner clover and a plurality of outer members forming an outer clover. The support frame can include gaps located between inner members of the plurality of inner members and outer members of the plurality of outer members. The inner clover can be radially inside the outer clover, and the outer clover can have larger dimensions than the inner clover. The support frames herein can be radially expandable and collapsible.