Extending the Depth of LED-based Photoacoustic Imaging for Carotid and Breast Applications

Abstract Light-emitting diode (LED)-based photoacoustic (PA) imaging offers a compact, safe, and cost-effective alternative to laser systems. However, low LED power leads to low optical fluence, which in turn limits penetration depth. We report a systematic optimization of LED-PA performance by jointly tuning ultrasound (US) probe frequency and LED pulse width, validated in both phantom and in vivo studies. Using a commercially available LED-PA/US platform, we compared a custom 5 MHz transducer with commercial 7 and 10 MHz probes under LED pulses of 30 to 100 ns. The 5 MHz probe with a 100 ns pulse achieved the best trade-off between depth sensitivity and resolution, enabling detection of targets up to 18 mm. In vivo experiments demonstrated, for the first time, clear visualization of the carotid artery and deep-seated breast vessels using LED-based PA imaging. These findings show that careful optimization of probe frequency and pulse width can substantially extend the depth performance of LED-PA, advancing its potential for vascular and oncologic applications.