A system for multiplexing photodetector signals from a scintillation detector. The system includes a detector module having a number of scintillator blocks, each scintillator block having a number of photosensors, and a number of multiplexing circuits. Each multiplexing circuit includes a number of inputs, a signal polarity inverter and at least one differential output attached to the signal polarity inverter. The multiplexing system inverts the polarity of preselected signals from the photosensors and selectively combines signals of different polarities to calculate event positioning and total energy.