Extending the wearable high-density diffuse optical tomography noise floor with SiPMs

Wearable high-density diffuse optical tomography (HD-DOT) systems often use PIN photodiodes rather than avalanche photodiodes (APDs), as their low bias voltages allow a smaller form factor, but make a tradeoff with noise performance as they lack the intrinsic gain of APDs. The use of silicon photomultipliers (SiPMs) in neuroimaging systems provides the opportunity to achieve the noise characteristics of fiber systems in the small format required for wearable HD-DOT systems. We integrate custom SiPM-based source/detector modules into an imaging cap, showing these improved noise characteristics extend the range of high-SNR measurements, increasing overall system channel count.