Performance characterization of light-emitting diode array-based photoacoustic computed tomography (LED-PACT)

We propose a cost-effective light emitting diode based photoacoustic computed tomography (LED-PACT) system integrating a custom nanosecond pulsed LED array with a single-element ultrasound transducer for circular scanning. An LED array consisting of 37 LEDs, driven by a homemade nanosecond pulsed current source (NSPCS) driver, provided 100 ns optical pulse width (850 nm wavelength), 0.18 mJ per pulse energy (8 kHz pulse repetition rate). We compared the performance of the LED-PACT in terms of imaging depth, resolution, signal-to-noise ratio (SNR) against pulsed laser diode (PLD) based PACT. Phantom and tissue studies demonstrate our LED-PACT's competitive imaging performance, including a SNR of 22.4 dB (with 2.25 MHz UST), comparable spatial resolution of 178 µm (with 5 MHz UST) and a practical imaging depth of 20 mm in chicken tissue, despite operating at significantly lower optical energies than PLD (0.18 mJ vs 1.88 mJ). With a fraction of cost (< $\$$ 1,000) compared to any other light sources used in PACT, this LED-PACT system holds promise for portable PA imaging system for widespread and safe clinical translation.