Disclosed is a calibration phantom for an x-ray imaging system having an x-ray source and an x-ray detector. The calibration phantom includes a combination of geometric objects of at least three different types and/or compositions including: a first object located in the middle, including a first material; a plurality of second objects arranged around the periphery of the first object, at least a subset of the second objects including a second material different than the first material, wherein the first object is relatively larger than the second objects; a plurality of third objects arranged around the periphery of the first object and/or around the periphery of at least a subset of the second objects, at least a subset of the third objects including a third material different than the first material and the second material, wherein the third objects are relatively smaller than the second objects.

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.

A dual-energy X-ray absorptiometry (“DXA”) system includes an x-ray source assembly comprising a source carriage to move the x-ray source assembly along a scan path, the scan path comprising an active scan portion and a reference measurement portion. A detector assembly including a detector carriage to move the detector assembly with the source assembly and to collect scan data at active scan portions. A support structure supporting the source and detector assemblies. A calibration controller coupled a calibration element having a known x-ray attenuation value and configured position the calibration element between the source and detector assemblies during the reference measurement portion and to remove the calibration element from between the source and detector assemblies during the active scan portion. A processing unit operable to compare the reference measurement against an expected reference value to identify a variance and to selectively trigger an action in response to the variance.

Disclosed herein is an image sensor with two radiation detectors, each having a planar surface for receiving radiation; and a calibration pattern. The planar surfaces of the radiation detectors are not coplanar. The image sensor can capture images of two portions of the calibration pattern, respectively using the radiation detectors. The image sensor can determine two transformations for the radiation detectors based on the images of the portions of the calibration pattern, respectively. The image sensor can capture images of two portions of a scene, respectively using the radiation detectors, determine projections of the images of the portions of the scene onto an image plane using the transformations, respectively, and form an image of the scene by stitching the projections.

Provided is a dynamic imaging quality control device that performs quality control concerning dynamic imaging in which dynamics of a subject is imaged by sequential radiation emissions to the subject. The dynamic imaging quality control device includes a hardware processor. The hardware processor presents information on the quality control. The information on the quality control includes at least one of information on a framerate, information on a system sensitivity, and information on an image region.

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.

A radiation imaging system operable to generate a plurality of radiation images based on different radiation energies, comprises: a communication unit configured to obtain at set communication intervals a temperature of a radiation tube by communication with a radiation generating unit; and a control unit configured to control, based on comparison of the temperature obtained at the communication intervals and a change rate of the temperature and respectively set threshold ranges, an operation for maintaining a driving state of the radiation tube or execution of image processing for obtaining a substance amount of a substance that forms an object using the plurality of radiation images.

Provided is a radiographic imaging device including: a first hardware processor; a sensor that includes multiple semiconductor elements arranged two-dimensionally and multiple switch elements respectively connected to the semiconductor elements; a gate driver that causes each of the switch elements of the sensor to switch between a conductive state and non-conductive state so as to release charge from each of the semiconductor elements; and a reader that performs readout of a signal value according to an amount of the charge released by the each of the semiconductor elements of the sensor. The first hardware processor sets an imaging condition that affects a dose of radiation reaching the sensor, selects a gate readout pattern according to the set imaging condition among different gate readout patterns, and drives the gate driver and the reader using the selected gate readout pattern.

A body thickness conversion unit converts a body thickness from a distance image imaged by a distance measurement camera to acquire the body thickness. A setting unit sets a gradation transformation function for use in gradation transformation processing to a radiographic image corresponding to the body thickness. A radiographic image acquisition unit acquires the radiographic image output from a radiation detector in radioscopy. A gradation transformation processing unit starts the gradation transformation processing with the gradation transformation function set by the setting unit.

Disclosed are a quantum dot population including a plurality of cadmium free quantum dots, a quantum dot polymer composite including the same, and a display device including the same. The plurality of cadmium free quantum dots includes: a semiconductor nanocrystal core comprising indium and phosphorous, a first semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core and comprising zinc and selenium, and a second semiconductor nanocrystal shell disposed on the first semiconductor nanocrystal shell and comprising zinc and sulfur, wherein an average particle size of the plurality of cadmium free quantum dots is greater than or equal to about 5.5 nm, a standard deviation of particle sizes of the plurality of cadmium free quantum dots is less than or equal to about 20% of the average particle size, and an average solidity of the plurality of cadmium free quantum dots is greater than or equal to about 0.85.