The present invention relates to determining baseline shift of an electrical signal generated by a photon detector (102) of an X-ray examination device (101). For this purpose, the photon detector comprises a processing unit (103) that is configured to determine a first crossing frequency of a first pulse height threshold by the electrical signal generated by the photon detector. The first pulse height threshold is located at a first edge of a noise peak in the pulse height spectrum of the electrical signal.

A measurement method for an air kerma conventional true value comprises: building a small-scale reference radiation field, then selecting a proper radiation source (4) and a source intensity for providing incident rays for a shielding box (1), subsequently selecting a plurality of gamma ray dose measurement instruments as experiment samples for building a prediction model to obtain a prediction model of the air kerma conventional true value of a check point, fmally placing a probe of an instrument to be detected on the check point (6), recording a scattering gamma spectrum detected by a gamma-ray spectrometer (9), and importing the prediction model to obtain the air kerma conventional true value. The method relates to the field of radiation protection detection or calibration, and has the beneficial effects that the result is accurate, the reference radiation field used is small in size, and the method is applied to measurement of the air kerma conventional true value. The method solves the problem that site and in-situ detection or calibration is unlikely to be implemented as the existing standard reference radiation field is too large in space and volume to move or is difficult to move.

A timing apparatus and method for a radiation detection, measurement, identification and imaging system are disclosed. The apparatus comprises high-energy photon detectors (100), a light pulse signal generator (300) and an optical fiber (200). Each high-energy photon detector (100) comprises a scintillation crystal and optical-to-electrical conversion multiplying devices. The high-energy photon detectors (100) are all provided with light transmission holes. Light pulse signals are propagated to the scintillation crystals through the light transmission holes (400), then propagated to the surfaces of the optical-to-electrical conversion multiplying devices through the scintillation crystals, converted and multiplied by the optical-to-electrical conversion multiplying devices, and processed and read by an electronic circuit. The high-energy photon detectors (100) independent from each other acquire absolute time from the light pulse signals generated by the light pulse generator (300) and timing and calibration are performed between the independent high-energy photon detectors (100). Timing is achieved through the time at which the optical-to-electrical multiplication devices receive the light pulse signals, decoupling between the high-energy photon detectors (100) can be realized, the independence of the high-energy photon detectors (100) is ensured, and thus the system can use, increase or decrease the high-energy photon detectors (100) more conveniently.

There is provided a method for at least partly determining the orientation of an edge-on x-ray detector with respect to the direction of x-rays from an x-ray source. The method includes obtaining (S1) information from measurements, performed by the x-ray detector, representing the intensity of the x-rays at a minimum of two different relative positions of a phantom in relation to the x-ray detector and the x-ray source, the phantom being situated between the x-ray source and the x-ray detector and designed to embed directional information in the x-ray field when exposed to x-rays. The method also includes determining (S2) at least one parameter associated with the orientation of the x-ray detector with respect to the direction of x-rays based on the obtained information from measurements and a geometrical model of the spatial configuration of the x-ray detector, x-ray source and phantom.

Intraoral three-dimensional (3D) tomosynthesis imaging systems, methods, and non-transitory computer readable media are used to generate one or more two-dimensional (2D) x-ray projection images and to reconstruct, using a computing platform, the one or more 2D x-ray projection images into one or more 3D images of an object, such as teeth of a patient, which can then be displayed on a monitor in order to enhance diagnostic accuracy of dental disease. The intraoral 3D tomosynthesis imaging system can include a wall-mountable control unit connected to one end of an articulating arm, the other end of which is connected to an x-ray source, which is configured to generate x-ray radiation that is acquired by an x-ray detector held at a desired position by an x-ray detector holder that is removably coupled to a collimator at an emission region of the x-ray source.

A SiPM tile includes SiPM arrays on a detector die, each of the SiPM arrays including a first plurality of microcells and a second plurality of reference microcells dispersed on the die, each reference microcell including an optically-opaque mask, a readout circuit each including a respective charge sensitive amplifier (CSA) connected to one of the reference microcells, each CSA configured to accumulate the dark current of the reference microcell during a selected time window, a hybrid temperature control circuit configured to receive an output signal from each CSA, and to determine the real-time temperature of the die based on the received output signal, to provide the real-time temperature to a temperature compensation and correction control unit that adjusts a cooling/heating system flow provided to the die, the adjustment based on the real-time temperature. A method for compensating the operating temperature variation of the SiPM tile is also disclosed.

A radiation detector assembly is provided that includes a semiconductor detector having a surface, plural pixelated anodes, and at least one processor. The pixelated anodes are disposed on the surface. Each pixelated anode is configured to generate a primary signal responsive to reception of a photon by the pixelated anode and to generate at least one secondary signal responsive to an induced charge caused by reception of a photon by at least one adjacent anode. The at least one processor is operably coupled to the pixelated anodes. The at least one processor configured to define sub-pixels for each pixelated anode; acquire signals corresponding to acquisition events from the pixelated anodes; determine sub-pixel locations for the acquisition events using the signals; and apply at least one calibration parameter on a per sub-pixel basis for the acquisition events based on the determined sub-pixel locations.

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.

Described here are systems and methods for optimization techniques for automatically selecting x-ray beam spectra, energy threshold, energy bin settings, and other imaging technique parameters for photon-counting detector computed tomography (“PCCT”). The techniques described here are generally based on subject or object size, material of interest, and location of the target material. Advantageously, the optimizations can be integrated with different PCCT systems to automatically select optimal imaging technique parameters before scanning a particular subject or object.

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.