Various aspects include methods for use in X-ray detectors for adjusting count measurements from pixel detectors within a pixelated detector module to correct for the effects of pileup events that occur when more than one photon is absorbed in a pixel detector during a deadtime of the detector system. In various embodiments, count measurements may be obtained at two different X-ray tube currents, from which the detector system deadtime may be calculated based on the two count measurements and a ratio of the two X-ray tube currents. Using the calculated deadtime, a pileup correction factor may be determined appropriate for the behavior of the detector system in response to pileup events. The pileup correction factor may be applied to pixel detector count values after the counts have been corrected for pixel-to-pixel differences using a flat field correction.

For dead time determination for a gamma camera or other detector, a long-lived point source of emissions is positioned so that the gamma camera detects the emissions from the source while also being used to detect emissions from the patient. The long-lived point source, in the scan time, acts as a fixed frequency source of emissions, allowing for dead time correction measurements that include the crystal detector effects.

A non-transitory computer-readable medium stores instructions readable and executable by a workstation (18) including at least one electronic processor (20) to perform an image reconstruction method (100). The method includes: determining singles rates of a plurality of radiation detectors (17) in a frame of imaging data detected by the radiation detectors; determining an energy correction factor (N.sub.wgt) for each detector for each radiation detector based on an energy spectrum distribution of gamma rays incident on the radiation detector during acquisition of the frame of imaging data; determining a singles live time correction factor for each radiation detector from the singles rate and the energy correction factor determined for the radiation detector; determining a system coincidence live time correction factor from the system singles rate; for each line of response (LOR) of a plurality of LORs connecting pairs of radiation detectors, determining a live time correction factor for the LOR from the determined singles live time correction factors of the pair of radiation detectors connected by the LOR and the determined system coincidence live time correction factor; and reconstructing the frame of imaging data using the determined LOR live time correction factors.

Aspects of the present disclosure relate to an energy-resolving photon counting detector pixel. Further aspects of the present disclosure relate to an energy-resolving photon counting detector comprising a plurality of such pixels, and to an energy-resolving photon counting system comprising the same.

In accordance with an aspect of the present disclosure, a CSA base level shift detector is used for determining a shift in the CSA base level over time relative to a first level. The pixel is configured to reset the CSA in dependence of the determined CSA base level shift.

A radiation sensor that may include a first transistor, a first isolated conductive structure that comprises a floating gate of the first transistor, a first group of radiation sensing diodes that are coupled to each other, wherein the first group is configured to convert sensed radiation that is sensed by the first group to a first output signal, and to change a state of the first isolated conductive structure using the first output signal, a second transistor, a second isolated conductive structure that comprises a floating gate of the second transistor, and a second group of radiation sensing diodes that are coupled to each other, wherein the second group is configured to convert sensed radiation that is sensed by the second group to a second output signal, and to change a state, under a control of the first transistor, of the second isolated conductive structure using the second output signal.

There are provided a storage section 220 that stores an output value read out by counting a pulse signal of incident X-rays, by a photon-counting type semiconductor detector; and a calculation section 230 that calculates a count value based on the output value that has been read out, wherein the calculation section 230 uses a model in which an apparent time constant of the pulse signal monotonously decreases against increase in pulse detection ratio with respect to exposure. According to such a model, the corresponding apparent time constant is able to be obtained even in any higher count rate. As a result of this, reduced can be the influence of count loss even on the count rate that has not been able to be covered by the conventional method.

An approach for counting particles suspended in a flow of gas or liquid in instruments that direct the flow through an illuminated region. Pulses are detected when the signal is below a threshold amplitude and moves above the threshold amplitude. This movement above the threshold creates a dead time during which only one pulse is detected until the signal amplitude moves sufficiently below the threshold such that a subsequent particle creates a distinct pulse. After counting the number of pulses, and determining the measured live time that the signal is below the threshold value, an initial particle concentration is calculated, and the calculation corrected for coincidence by calculating an actual live time as a measured live time minus a constant multiplied by the number of distinctly counted pulses, where the constant has the units of time. From this, particle concentrations in a volume can be determined.

One embodiment is a method for binning charge events in a photon-counting CT scanning system comprising a plurality of discriminators, wherein each discriminator is associated with a respective one of a plurality of threshold voltage levels, the method comprising detecting a transition in a signal output from one of the discriminators; and incrementing a count corresponding to the threshold voltage level associated with the one of the discriminators only if the detected discriminator output signal transition was immediately preceded by an opposite transition in the discriminator output signal.

The present invention relates to a system (100) and a method for correcting a number of counts (115) in an energy bin of X-ray photons detected by a photon counting detector (111) for a spectral computed tomography system (300). An illumination history (125) of the photon counting detector is taken into account to determine a gain and/or an offset of the photon counting detector. The number of counts in an energy bin of detected photons is corrected according to a correction value (135) corresponding to the determined gain and/or offset.

A radiation-sensitive device is disclosed. The radiation-sensitive device includes: a plurality of single photon avalanche diodes (SPADs), and processing circuitry configured to determine an intensity of incident radiation using at least one of the plurality SPADs. An amount of the SPADs used to determine the intensity of the incident radiation varies in relation to the intensity of the incident radiation. Also disclosed in an associated method of determining an intensity of radiation incident upon such a radiation-sensitive device, and uses of the radiation-sensitive device in an electronic-nose or point-of-care apparatus, or for ambient light sensing.