Time-based digitizer for PET photodetector

摘要

An integrated circuit in a PET imaging system with a plurality of photo detectors is provided. A plurality of differential transimpedance amplifiers with differential inputs and differential outputs is provided, wherein differential inputs for each differential transimpedance amplifier of the plurality of differential transimpedance amplifiers are electrically connected to a photodetector. A plurality of level crossing analog-to-digital converters is provided wherein differential inputs for each level crossing analog-to-digital converter of the plurality of level crossing analog-to-digital converters are electrically connected to differential outputs of a differential transimpedance amplifier, wherein each level crossing analog-to-digital converter of the plurality of level crossing analog-to-digital converters, comprises a plurality of differential comparators with differential inputs and differential threshold inputs, wherein the differential inputs are electrically connected to the output of the differential outputs of the differential transimpedance amplifier electrically connected to the level crossing analog-to-digital converter and a clock.

主权项

1. An integrated circuit in a PET imaging system with a plurality of photodetectors, wherein the plurality of photodetectors are optically coupled to scintillation crystals for a PET scanner, comprising:
a plurality of differential transimpedance amplifiers with differential inputs and differential outputs, wherein differential inputs for each differential transimpedance amplifier of the plurality of differential transimpedance amplifiers are electrically connected to a photodetector of the plurality of photodetectors; a plurality of level crossing analog-to-digital converters wherein differential inputs for each level crossing analog-to-digital converter of the plurality of level crossing analog-to-digital converters are electrically connected to differential outputs of a differential transimpedance amplifier of the plurality of differential transimpedance amplifiers, wherein each level crossing analog-to-digital converter of the plurality of level crossing analog-to-digital converters, comprises:
a plurality of differential comparators with differential inputs and differential threshold inputs, wherein the differential inputs are electrically connected to the output of the differential outputs of the differential transimpedance amplifier of the plurality of differential transimpedance amplifiers electrically connected to the level crossing analog-to-digital converter; anda clock for providing a time stamp, wherein each level crossing analog-to-digital converter of the plurality of level crossing analog-to-digital converters, further comprises a plurality of flip flops, wherein each flip flop receives input from a differential comparator of the plurality of differential comparators and the clock, wherein clock output is provided to a D input of each flip flop and differential comparator output is provided as input to a clock terminal of each flip flop, wherein output of each flip flop provides a digital representation of a shape of a current pulse waveform from a photodetector of the plurality of photodetectors.