ABSTRACT
Photoacoustic tomography (PAT), combining optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale non-ionizing functional and molecular imaging. Light offers rich tissue contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) 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 due to thermoelastic expansion. 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. 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 systems biology and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. PAT may also hold the key to the earliest detection of cancer by in vivo label-free quantification of hypermetabolism, the quintessential hallmark of cancer. The technology is commercialized by several companies.
BIO
Lihong V. Wang, PhD, is a Gene K. Beare Distinguished Professor and Director of the Optical Imaging Laboratory, Department of Biomedical Engineering, at Washington University in St. Louis.
Dr. Lihong Wang earned his PhD degree at Rice University, TX, and currently holds the Gene K. Beare Distinguished Professorship of Biomedical Engineering at Washington University in St. Louis. He published over 255 peer-reviewed journal articles and delivered over 270 keynote, plenary, and invited talks. Professor Wang and his lab invented or discovered functional photoacoustic tomography, dark-field confocal photoacoustic microscopy (PAM), optical-resolution PAM, photoacoustic Doppler effect, photoacoustic reporter gene imaging, focused scanning microwave-induced thermoacoustic tomography, the universal photoacoustic or thermoacoustic tomography, the universal photoacoustic or thermoacoustic reconstruction algorithm, frequency-swept ultrasound-modulated optical tomography, time-reversed ultrasonically encoded (TRUE) optical focusing, sonoluminescence tomography, Mueller-matrix optical coherence tomography, optical coherence computed tomography, and oblique-incidence reflectometry. He received over 28 research grants as the principal investigator, with a cumulative budget of over $31M, including NIH’s FIRST and NSF’s CAREER awards.
Professor Wang is a Fellow of the AIMBE (American Institute for Medical and Biological Engineering), OSA (Optical Society of America), IEEE (Institute of Electrical and Electronics Engineers), and SPIE (Society of Photo-Optical Instrumentation Engineers). He is the Editor-in-Chief of the Journal of Biomedical Optics, chairs the annual conference on Photons plus Ultrasound, and chaired the 2010 Gordon Conference on Lasers in Medicine and Biology and the 2010 OSA Topical Meeting on Biomedical Optics. Dr. Wang serves as the founding chair of the scientific advisory boards for two companies commercializing his inventions. He was awarded the C. E. K. Mees Medal for “seminal contributions to photoacoustic tomography and Monte Carlo modeling of photon transport in biological tissues and for leadership in the international biophotonics community”.
