A multichannel application specific integrated circuit (ASIC) for interfacing with an array of photodetectors in a positron emission tomography (PET) imaging system includes a front end circuit configured to be coupled to the photodetectors and to receive discrete analog signals therefrom. The ASIC further includes a time discriminating circuit operably coupled to the front end circuit and configured to generate a hit signal based on a combination of the discrete analog signals, and an energy discriminating circuit operably coupled to the front end circuit and configured to generate a summed energy output signal based on each of the discrete analog signals and summed row and column output signals based on each of the discrete analog signals. The summed energy output signal represents an energy level of the detected radiation in the array of photodetectors, and the summed row and column output signals represent a location of the detected radiation.