Temporally delayed, dual-pulse, dual-wavelength photoacoustic imaging (TD-DP-DW-PAI): advancing capabilities of a commercial light-emitting diode-based photoacoustic imaging system with a pulsed laser diode

Photoacoustic imaging (PAI) is a hybrid imaging technique providing optical contrast with ultrasound resolution for deep tissue imaging. Typical light sources used for PAI include pulsed lasers, pulsed laser diode (PLD), and light-emitting diodes (LED). LED is the most economical light source among these, and there are commercial photoacoustic + ultrasound imaging (PAUS) systems with LED-based light illumination. However, LEDs have low energy per pulse compared to pulsed lasers and PLDs, leading to limited applications. Therefore, in this work, we demonstrate temporally delayed, dual-pulse, dual-wavelength photoacoustic imaging (TD-DP-DW-PAI) using an additional PLD illumination to enhance the performance and functionality of a commercial LED-based PAUS system. Three key improvements were demonstrated with phantom imaging - image quality enhancement, imaging frame rate enhancement, and functional imaging enhancement (multispectral imaging) without compromising the frame rate. We demonstrated signal-to-noise improvement by a factor of two, non-linear doubling of the frame rate, and multi-wavelength imaging without compromising the LED's low energy illumination and frame rate.