A hybrid multiplexer readout circuit one dimensional resistive charge division (1D-RCD) chain and winner
takes all (WTA) circuit was proposed for MR-compatible PET detector modules. To prove the effectiveness of
the circuit, three different readout circuits including WTA, 2D-RCD and proposed hybrid RCD-WTA multiplexer
were evaluated for 4 × 4 LYSO-GAPD PET detector. Various parameters were precisely measured and
quantitatively characterized. While there were considerable differences observed in rise time, fall time, pulse
width and amplitude of analog output waveforms for each circuit, the detector performance was quite similar
in crystal identification and energy resolution. However, pincushion distortion was observed in the flood histogram
of 2D-RCD, and spatial linearity was relatively degraded. The coincidence time resolutions were 487 ps,
955 ps, and 676 ps for WTA, 2D-RCD, and hybrid RCD-WTA multiplexer, respectively. These results demonstrated
that proposed hybrid multiplexer could effectively reduce the number of analog electronic channels
from N² to only 2 for an N × N photosensor array, while maintaining intrinsic performance of multichannel
PET detector requiring energy, position and time information for incidence photons.