Abstract: A method and a system for providing calibration for a photon counting CT detector forward model for material decomposition. Various slabs of predetermined material and path lengths are placed in the photon counting CT detector and scanned using one or more stationary X-rays to obtain calibration data and parametrize the forward model.

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.

Abstract: A photon counting detector (PCD) apparatus includes a PCD array including a plurality of micro-pixels positioned in at least one of a channel direction and a row direction; and processing circuitry configured to: receive signals from each of the plurality of micro-pixels; configure the PCD array to include (a) a first micro-pixel area including a first group of plural micro-pixels of the plurality of micro-pixels and (b) a second micro-pixel area including a second group of plural micro-pixels of the plurality of micro-pixels, such that a portion of the first and second groups of plural micro-pixels overlap between the first and second groups; bin the signals from the first group of plural micro-pixels into a first virtual bin value; and bin the signals from the second group of plural micro-pixels into a second virtual bin value.

Abstract: A photon counting computed tomography (CT) method including, but not limited to, receiving a first forward model including a set of first parameters and a set of second parameters corresponding to a plurality of materials and path lengths by scanning a slab at plural tube voltages and plural tube currents of an X-ray tube; evaluating an image quality of a material decomposition image reconstructed by the set of first parameters and the set of second parameters; and updating at least one second parameters from the set of second parameters if the image quality of the material decomposition image does not satisfy a predetermined threshold, wherein the update of the at least one second parameter from the set of second parameters is achieved by updating the at least one second parameter from the set of second parameters to an energy dependent parameter from a constant value. Processing circuitry that is part of a photon counting computed tomography (CT) can implement the method.

Abstract: A method and apparatus for diagnosing and/or calibrating underperforming pixels in detectors in a small pixelated photon counting CT system utilizes a series of tests on image data acquired in-situ as part of a series of calibration scans in the CT system. Tests are performed on the acquired data to determine the existence of underperforming pixels within the detectors such that the information acquired by those pixels can be replaced by alternate data from surrounding pixels (e.g. by interpolation). The underperforming pixels are stored in “bad” pixel tables and may be specific to a type of image (e.g., spectral or counting) and a specific protocol.

Abstract: A method and a system for providing calibration for a polychromatic photon counting detector forward counting model. Measurements with multiple materials and known path lengths are used to calibrate the photon counting detector counting response of the forward model. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. The beam hardening corrections are then applied to the measured projection data sinogram, and the corrected sinogram is reconstructed to the counting image at the selected single energy.

Abstract: A method and a system for providing calibration for a polychromatic photon counting detector forward counting model. Measurements with multiple materials and known path lengths are used to calibrate the photon counting detector counting response of the forward model. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. The beam hardening corrections are then applied to the measured projection data sinogram, and the corrected sinogram is reconstructed to the counting image at the selected single energy.

Abstract: A method and a system for a two-step calibration method for the polychromatic semiconductor-based PCD forward counting model, to account for various pixel summing readout modes for imaging at different resolutions. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. To correct the variation of the detector response due to different PCD sub-pixel summing schemes, the embodiments calibrate forward model parameters based on the various pixel readout modes.

Abstract: An apparatus, system and method for calibrating an x-ray apparatus including acquiring sinogram data by scanning a symmetrical phantom using a plurality of detector channels; generating mirror-copied sinogram data by mirror-copying at least one of first sinogram data and second sinogram data of the acquired sinogram data, wherein the first sinogram data and the second sinogram data are generated by dividing the sinogram data at a center detector channel of the plurality of detector channels; outputting a first reconstructed image by reconstructing the mirror-copied sinogram data; and determining a calibration parameter based on the first reconstructed image.

Abstract: A method and apparatus for diagnosing and/or calibrating underperforming pixels in detectors in a small pixelated photon counting CT system utilizes a series of tests on image data acquired in-situ as part of a series of calibration scans in the CT system. Tests are performed on the acquired data to determine the existence of underperforming pixels within the detectors such that the information acquired by those pixels can be replaced by alternate data from surrounding pixels (e.g. by interpolation). The underperforming pixels are stored in “bad” pixel tables and may be specific to a type of image (e.g., spectral or counting) and a specific protocol.

Abstract: A method and a system for providing calibration for a photon counting CT detector forward model for material decomposition. Various slabs of predetermined material and path lengths are placed in the photon counting CT detector and scanned using one or more stationary X-rays to obtain calibration data and parametrize the forward model.

Abstract: An apparatus, system and method for calibrating an x-ray apparatus including acquiring sinogram data by scanning a symmetrical phantom using a plurality of detector channels; generating mirror-copied sinogram data by mirror-copying at least one of first sinogram data and second sinogram data of the acquired sinogram data, wherein the first sinogram data and the second sinogram data are generated by dividing the sinogram data at a center detector channel of the plurality of detector channels; outputting a first reconstructed image by reconstructing the mirror-copied sinogram data; and determining a calibration parameter based on the first reconstructed image.

Abstract: A method and a system for providing calibration for a polychromatic photon counting detector forward counting model. Measurements with multiple materials and known path lengths are used to calibrate the photon counting detector counting response of the forward model. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. The beam hardening corrections are then applied to the measured projection data sinogram, and the corrected sinogram is reconstructed to the counting image at the selected single energy.

Abstract: A method and a system for a two-step calibration method for the polychromatic semiconductor-based PCD forward counting model, to account for various pixel summing readout modes for imaging at different resolutions. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at plural tube voltage settings for each detector pixel. To correct the variation of the detector response due to different PCD sub-pixel summing schemes, the embodiments calibrate forward model parameters based on the various pixel readout modes.

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.

Abstract: A CANopen-based data transmission gateway changeover method includes: making an active gateway go alive, and mutually monitoring heartbeat packet status together with a standby gateway over an active-standby gateway communications network; keeping the active gateway alive and recording a breakdown of the standby gateway if no heartbeat packet of the standby gateway is detected within a preset heartbeat period and a heartbeat packet of the active gateway is successfully transmitted on the active-standby gateway communications network; requesting the standby gateway to go alive if the heartbeat packet of the active gateway fails to be transmitted on the active-standby gateway communications network; stopping requesting the standby gateway in a first in-vehicle communications network to go alive, and requesting the standby gateway to go alive; and keeping the active gateway alive and recording a breakdown of the standby gateway if still no response is received from the standby gateway.

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.

Abstract: An embodiment of a computed tomography apparatus includes an x-ray source and scan control circuitry configured to control the x-ray source to expose a subject with x-rays over a scan having a plurality of views. A detector is disposed to receive x-rays from the x-ray source, has a plurality of anodes arranged in groups, and a common conductive strip between the anodes. Photon counting circuits are respectively provided for each of the anodes and have adjustable operating parameters. Connection circuitry is configured to adaptively connect, in a first mode, each anode to one of the photon counting circuits and, in a second mode, each anode in a group to a same one of the photon counting circuits. Processing circuitry, connected to the connection circuitry and the photon counting circuits, is configured to, for each of the views, select the first mode or the second mode and adjust the operating parameters based upon exposure data obtained from exposing the subject with the x-rays from the x-ray source.

Abstract: An embodiment of a computed tomography apparatus includes an x-ray source and scan control circuity configured to control the x-ray source to expose a subject with x-rays over a scan having a plurality of views. A detector is disposed to receive x-rays from the x-ray source, has a plurality of anodes arranged in groups, and a common conductive strip between the anodes. Photon counting circuits are respectively provided for each of the anodes and have adjustable operating parameters. Connection circuitry is configured to adaptively connect, in a first mode, each anode to one of the photon counting circuits and, in a second mode, each anode in a group to a same one of the photon counting circuits. Processing circuitry, connected to the connection circuitry and the photon counting circuits, is configured to, for each of the views, select the first mode or the second mode and adjust the operating parameters based upon exposure data obtained from exposing the subject with the x-rays from the x-ray source.

Abstract: A method and a system for providing calibration for a photon counting detector forward model for material decomposition. The flux independent weighted bin response function is estimated using the expectation maximization method, and then used to estimate the pileup correction terms at each tube voltage setting for each detector pixel.