Readout network topology for positron emission tomography devices with Time-of-Flight

An imaging system, comprising:

• a plurality of readout networks for positron emission tomography (PET), wherein each readout network has time of flight (TOF) capabilities to extract position and time information in the area of gamma-ray detection, each readout network further comprises:
• a plurality of individual photodetectors arranged in a p×q matrix configuration on an electronic Printed Circuit Board (PCB) to conform a photodetector capable to process light arriving to a matrix area and providing information to determine spatial coordinates and a timing signal, each individual photodetector having an anodic terminal and a cathodic terminal;
• a connection of all similar terminals of one of the two types of the photodetector, terminals, either anodes or cathodes, to a Single Junction at the PCB, which further splits into two routes:
• the first one of these routes connects the Single Junction, by a specific impedance, to a proper source polarity, wherein the proper source polarity is Vbias if the similar terminals to the Single Junction are the cathodes or GND if the similar terminals to the Single Junction are the anodes, and wherein the specific impedance:
• is Za if the similar terminals are the anodes or Zk if the similar terminals are the cathodes,
• is working as part of a photodetector bias circuit, and
• has a resistance set to be less than 10% compared to a resistance of a remainder of the first route from the Single Junction to GND;
• and
• the second one of these routes is connected to a unified signal created at the Single Junction, into a fast amplifier, in order to obtain a single timing signal regarding the photodetector, no matter which of the plurality of individual photodetectors it comes from;
• an individual connection of all other photodetector terminals, different from the similar terminals connected to the Single Junction, by two separate types of filtering circuits for each of the other photodetector terminals,
• the first type of filtering circuits connecting the individual photodetector terminals to the proper source polarity to complete the bias circuits for all individual photodetectors;
• and,
• the second type of filtering circuits functioning as output signal filters, to obtain individual current signals from each individual photodetector, representing the quantity of light captured by each individual photodetector in the matrix, giving rise to uncoupled Xi signals.

A method for obtaining time and position information from the signals coming from a ToF-PET photodetector, in a detector module of a PET device, the method comprising the steps of:

• arranging a scintillation crystal in a detector module;
• arranging a readout network topology for positron emission tomography (PET) with time of flight (TOF) capabilities to extract position and time information in an area of gamma-ray detection, said readout network topology comprising:
• a plurality of individual photodetectors arranged in a p×q matrix configuration on an electronic Printed Circuit Board (PCB) to conform a photodetector capable to process light arriving to a matrix area and providing information to determine spatial coordinates and a timing signal, each individual photodetector having an anodic terminal and a cathodic terminal;
• a connection of all similar terminals of one of the two types of the photodetector terminals, either anodes or cathodes, to a Single Junction at the PCB, which further splits into two routes:
• the first one of these routes connects the Single Junction, by a specific impedance, to a proper source polarity, wherein the proper source polarity is Vbias if the similar terminals to the Single Junction are the cathodes or GND if the similar terminals to the Single Junction are the anodes, and wherein the specific impedance:
• is Za if the similar terminals are the anodes or Zk if the similar terminals are the cathodes,
• is working as part of a photodetector bias circuit, and
• has a resistance set to be less than 10% compared to a resistance of a remainder of the first route from the Single Junction to GND;
• and
• the second one of these routes is connected to a unified signal created at the Single Junction, into a fast amplifier, in order to obtain a single timing signal regarding the photodetector, no matter which of the plurality of individual photodetectors it comes from;
• an individual connection of all other photodetector terminals, different from the similar terminals connected to the Single Junction, by two separate types of filtering circuits for each of the other photodetector terminals,
• the first type of filtering circuits connecting the individual photodetector terminals to the proper source polarity to complete the bias circuits for all individual photodetectors;
• and,
• the second type of filtering circuits function as output signal filters, to obtain individual current signals from each individual photodetector, representing a quantity of light captured by each individual photodetector in the matrix, giving rise to uncoupled Xi signals;
• receiving a gamma ray into the detector module and impinging the scintillation crystal;
• creating a light beam from the gamma ray incident on the scintillation crystal which is emitted out from the scintillation crystal to the readout network topology;
• converting the light beam into a distribution of electrical signals coming from the plurality of individual photodetectors,
• providing a first signal detected from any one of the plurality of individual photodetectors to a fast amplifier, the first signal corresponding to the instant of the arrival of the gamma ray to the scintillator crystal volume;
• generating an output timing signal from the fast amplifier;
• transmitting the electrical signals from each of the plurality of individual photodetectors via charge filters to provide uncoupled charge signal outputs compatible with readout electronic circuits used to extract position and energy of the gamma ray.