MedE Distinguished Speaker

Abstract: Photoacoustic tomography (PAT) provides in vivo multiscale non-ionizing functional and molecular imaging by combining optical and ultrasonic waves via the photoacoustic effect. High-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) offers rich tissue contrast but is limited to depths within the optical diffusion limit (~1 mm in the skin). In PAT, pulsed laser light penetrates the tissue and generates a small but rapid temperature rise, which induces emission of ultrasonic waves. The ultrasonic waves, ~1000 times less scattering than optical waves in tissue, are then detected to form high-resolution images at depths up to 7 cm, breaking through the optical diffusion limit. Super-resolution beyond the optical diffraction limit has also been achieved. PAT is the only modality capable of imaging across the length scales of organelles, cells, tissues, and organs with consistent contrast. Such a technology has the potential to enable multiscale biology and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. PAT has been commercialized by several companies. The annual conference on this topic has become the largest in SPIE's Photonics West as of 2010.