A multichannel ASIC for interfacing with an array of photodetectors in a PET imaging system includes a front-end circuit configured to be coupled to the array of photodetectors and to receive analog signals therefrom. The ASIC includes a time discriminating circuit including a low input impedance amplifier configured to be coupled to the array of photodetectors and to receive a signal summing the analog signals from the array of photodetectors and to generate a hit signal for timing pickoff based on the signal. The ASIC includes an energy circuit operably coupled to the front-end circuit and configured to generate a summed energy output signal based on each of the analog signals and summed positional output signal based on each of the analog signals.

Embodiments include a method, comprising: receiving measured radiation obtained from a radiation detector that received radiation through an object; simulating the measured radiation obtained from the radiation detector that received radiation through the object; generating an offset based on the measured radiation and the simulated measured radiation; estimating scatter radiation based on the offset; and estimating primary radiation based on the estimated scatter radiation.

An on-line energy coincidence method for an all-digital PET system, comprising: a detection module conducting information collection on a scintillation pulse, forming a single event data frame and sending it to an upper computer; the upper computer conducting two-bit position distribution statistics on an incident gamma photon event and conducting position spectrum partition; performing statistics on an energy distribution spectrum of each crystal bar, so as to acquire an energy correction value; the detection module uploading a crystal bar partition data table and an energy peak correction data table; starting information collection of on-line energy correction; when an event is coming, according to a two-dimensional coordinate thereof, from the crystal partition table, searching for a crystal bar number corresponding thereto, and searching for an energy correction value from the energy correction table; and sending data passing the energy coincidence to the upper computer.

A channel multiplexing method for reading out a detector signal is provided, including steps: grouping L detectors to form a first source signal and a second source signal; respectively introducing L detector signals into a first signal transmission line including two readout channels A and B and a second signal transmission line including two readout channels C and D, and providing a first signal delay unit and a second signal delay unit on the first signal transmission line and the second signal transmission line; and symbolizing source detectors for forming signals according to pulses of the four readout channels A, B, C and D, and obtaining final pulse information.

A SiPM sensor chip with a plurality of pixels includes a photodiode; a quench resistor; and a current divider configured to divide the photocurrent of the photodiodes into two currents of equal size. The current divider Sq,nm or Snm lead to networks NS,h,n and NS,V,m, each of which leads to additional current dividers Sh,n and Sv m having coding resistors Rh,A,n and Rh,B,n, and Rv,c,m and Rv D m, which are linearly coded and which lead to output channels A, B, C, D, with these sensor features being integrated into the sensor chip. The networks Ns,h,n and/or NSiVlm each lead to a summation network Oh and/or Ov, in which the signals of the networks Ns,h,n and/or NS,v,m are merged via summation resistors Rs,h,n and Rs,v,m, respectively, and lead to the output channels E and/or F.

A system (10) and a method (100) compensate for one or more dead pixels in positron emission tomography (PET) imaging. A pixel compensation processor receives PET data describing a target volume of a subject. The PET data is missing data for one or more dead pixels. The pixel compensation estimates PET data for the dead pixels from the received PET data.

Model-based scatter correction is used in SPECT with a non-parallel-hole collimator. Model-based scatter correction uses scatter kernels based on simulation to model the scatter for a given system and patient. For non-parallel-hole collimators, the measured sensitivity and measured vector maps are used in the modeling of scatter. The measured sensitivity is used to normalize the scatter kernels simulated for a parallel-hole collimator rather than attempting to simulate scatter with the complicated arrangement of holes. The measured vector maps are used to accurately project the model-based scatter sources into a data or emissions space.

In a radiation detector, an output extraction portion includes a first resistor chain, a first light detection portion of each of a plurality of radiation detection units being connected to the first resistor chain, and a second resistor chain, a second light detection portion of each of the plurality of radiation detection units being connected to the second resistor chain.

A system for low-count quantitative single-photon emission computed tomography (LC-QSPECT) is provided. The system is programmed to a) store a computer tomography (CT) scan of a subject being examining including a plurality of defined volumes of interest (VOIs) of the subject being examined; b) model a system matrix based on the stored CT, wherein the model describes the probability that photons emitted from each of the defined VOIs are detected in different projection bins, wherein a plurality of projection bins are defined around the subject and the defined VOIs; c) adjust the model with analysis of stray-radiation noise around the subject; d) detect, by the one or more sensors, one or more photons being emitted by an alpha-particle-emitting isotope; and e) execute the adjusted model with the one or more detected photons as inputs to determine a source VOI of the detected photons.

A method includes accumulating counts for each pixel in a set of pixels of one or more gamma cameras of a SPECT imaging system from a plurality of imaging examinations and each energy peak of each isotope used in the plurality of imaging examinations to produce an energy spectrum for each of the pixels at each of the energy peaks of each of the isotopes, determining, for the pixels and for the energy peaks, an energy calibration factor that converts an energy detected by each of the pixels to an energy of a corresponding energy peak and populating an energy map with the factors, and determining, for the pixels and for the energy peaks, a uniformity calibration factor that converts a number of counts detected by each of the pixels to a predetermined number of counts for a corresponding energy peak and populating a uniformity map with the factors.