Real-time swept-beam compact photoacoustic/ultrasound imaging system (Conference Presentation)

Abstract

Photoacoustic (PA) imaging has had limited clinical applicability for many reasons but one primary barrier to clinical translation is the bulky, expensive, and low repetition-rate laser typically used, resulting in low frame-rate images and a system with a large physical footprint. We have previously demonstrated a fast-scan approach delivering the frame rates required for real-time integrated PA/ultrasound (PAUS) imaging. In this paper, we present a new real-time PAUS system based on a swept-scanning source approach using a compact, recently-developed laser, providing pulse-to-pulse wavelength tuning at kHz rates and a scanning fiber-optic delivery system integrated with a high-frequency (15 MHz) US linear array. An array of fibers spanning the array are arranged on two lateral sides of the transducer and scanned sequentially based on optimized pulse sequences. By coherent compounding of multiple sub-images associated with each fiber light source, PA imaging with sufficient SNR at a frame rate of 50 Hz is achieved. Real-time in vivo multi-spectral imaging of nano-drug delivery to mice is demonstrated. With the same scanner footprint, our compact PAUS system can provide not only conventional high-quality scanned US imaging with all associated modes, but interleaved, multispectral PA imaging at video rates appropriate for real-time clinical applications.