An instrument and software methodology to detect a radioactive source and incorporates the following:

1) two radiation detectors in a co-axial configuration, housed in a handheld probe, and

2) a gamma detection control unit executing software algorithms to limit the functional field of view to the front aspect of the probe, vary the depth and width of the field of view to provide collimation without the use of metallic shielding, and allowing the instrument to measure the distance to the radiation source.

The present invention relates to a calibration method for a gamma ray detector (100) including a pixelated scintillator array (110) for emitting scintillation photons at photo conversion positions (94) in response to incident gamma rays (90), and a pixelated photodetector array (120) for determining a spatial intensity distribution of the scintillation photons. The present invention bases on the idea that using the concept of optical light sharing of scintillation photons, which are emitted in one element, i.e., one scintillator pixel (112) of the scintillator array (110) and distributed over multiple photodetector pixels (122) of the pixelated photodetector array (120), allows obtaining an estimate for the time skew between adjacent photodetector pixels (122). The present invention further relates to a calibration module (200) for a gamma ray detector (100) including a recorder (210) and a processing module (220) for performing the function of the above-explained method. Still further, the present invention relates to a gamma ray detector (100) as well as to a medical imaging device (50) comprising this gamma ray detector (100).

Systems and methods to estimated mean randoms include acquisition of list mode data describing true coincidences and delay coincidences detected by a positron emission tomography scanner during a scan of an object, determination, for each crystal of the positron emission tomography scanner and for each of a plurality of time periods of the scan, of delay coincidences including the crystal based on the list mode data, determination, each crystal, of determine a singles rate associated with each time period based on the delay coincidences determined for the crystal over the time period, determination, for each time period, of determine estimated mean randoms for each of a plurality of pairs of the crystals based on the singles rate associated with the time period for each crystal of the crystal pair, and reconstruction of an image of the object based on the estimated mean randoms for each time period and the detected true coincidences.

The present disclosure provides an imaging system and method for nuclear medicine imaging. The imaging system may include a detector and a collimator. The detector may be configured to detect photons. The collimator may have at least two sets of pinholes. The at least two sets of pinholes may include a first set of first pinholes and a second set of second pinholes. Each second pinhole of the second set of second pinholes may be equipped with a filter configured to filter the photons.

For positron emission tomography (PET) detector gain stabilization despite temperature variation, an open loop gain control based on temperature establishes a baseline gain despite possible temperature variation. The baseline gain is then adjusted with a more sensitive closed-loop (e.g., peak tracking) approach for dealing with temperature. By combining both types of gain control to deal with temperature, the advantages of both are provided while avoiding disadvantages of either approach by itself.

Provided is a silicon photomultiplier (SiPM) device and a silicon photomultiplier based LiDAR. The SiPM device includes a first sub-region and a second sub-region. In the first sub-region, the photodiode is operated with a first internal gain. In the second sub-region, the photodiode is operated with a second internal gain and the second internal gain in smaller than the first internal gain. A first anode generates current from the first sub-region in response to a low flux event, and the second anode generates current from the second sub-region in response to a high flux event. A common cathode outputs current generated from the first sub-region or the second sub-region.

A photon counting circuit, a radiographic imaging apparatus, and a threshold setting method are provided, in which the photon counting circuit is capable of sufficiently reducing a difference between a target threshold value and a threshold value set for a pixel even if each pixel of a photon counting detector is divided into a plurality of subpixels. In the photon counting circuit for counting, for each pixel, electrical charges generated depending on photon energy of radiation applied to an object, a pixel is divided into a plurality of subpixels. When N is a natural number, a threshold value of each of the subpixels is selected from among top N discrete values of a plurality of discrete values arranged in order of proximity to a target threshold value corresponding to the photon energy so as to minimize a difference between the target threshold value and an average of the threshold values of the respective subpixels included in the pixel.

A signal readout circuit is a circuit for reading out a signal from a photodetection element having a plurality of photodetection pixels each generating a detection signal according to light incidence, and includes N light incidence detection units (N is an integer of 2 or more) each for inputting the detection signal from each of N photodetection pixels and outputting a signal indicating the light incidence, and a total value detection unit for detecting a total value of the output signals from the N light incidence detection units. Each light incidence detection unit outputs the signal weighted differently corresponding to each photodetection pixel. A weight thereof is set such that the total values are different for respective photodetection pixels and all combination patterns of the photodetection pixels.

A two-dimensional imaging system and a two-dimensional or three-dimensional optical tomographic mapping system, each employing gas scintillation induced by ionizing radiation, i.e., radioluminescence, and corresponding methods, are disclosed. The systems may employ one or more cameras and corresponding UV filters (potentially solar blind filters) for imaging a radioluminescent scene. For two-dimensional or three-dimensional mapping, the resultant UV images are spatially registered with one another and then reconstructed to form a three-dimensional tomographic map of the ionizing radiation. The two-dimensional map is a plane of the three-dimensional map. The UV images may be spatially registered by using a reference source, optionally, a calibrated reference source allowing dosimetry calculations for the ionizing radiation. Molecular nitrogen is the primary candidate for the radioluminescent gas, though a controlled ambient in a chamber of nitric oxide, argon, krypton, or xenon may be employed. The reconstruction process employs an algebraic reconstruction technique or an Abel inversion.

The present invention relates to a Compton imaging apparatus and a single photon emission and positron emission tomography system comprising the Compton imaging apparatus and, more specifically, to a Compton imaging apparatus based on a single scintillator and a single photon emission and positron emission tomography system including the Compton imaging apparatus. The Compton imaging apparatus according to the present invention may reconstruct a Compton image based on the single scintillator composed of a plurality of scintillation cells. Thus, the Compton imaging apparatus of the present invention is cheaper than any other Compton imaging apparatuses and has an excellent time resolution such that the Compton imaging apparatus can be used even in a high-radiation area. Also, the single photon emission and positron emission tomography system using the Compton imaging apparatus can improve radiation detection efficiency and an image resolution, to thereby improve image quality.