Non-contact laser ultrasound

Xiang (Shawn) Zhang
Postdoctoral Associate, Mechanical Engineering (MechE)

2020 SENSE.nano Symposium
Monday, September 21, 2020
Session 2: Organs
3:35PM – 3:50PM EST

Abstract
Full non-contact laser ultrasound (LUS) imaging has several distinct advantages over current medical ultrasound (US) technologies: elimination of coupling mediums (gel/water), operator-independent image quality, improved repeatability, and volumetric imaging. Current light-based ultrasound utilizing tissue penetrating photoacoustics (PA) generally uses traditional piezoelectric transducers in contact with the imaged tissue or carries an optical fiber detector close to the imaging site. Unlike PA, LUS minimizes optical penetration and specifically restricts optical to acoustic energy transduction at the tissue surface, maximizing the generated acoustic source amplitude. LUS operates analogous to conventional ultrasound by using light to replace piezoelectric elements. Experimental LUS images at ~5 cm image depths with meter scale standoff successfully demonstrates the feasibility of LUS for human imaging at eye and skin safe optical exposure levels. First human LUS images inspire further LUS development and is a significant step toward clinical implementation of LUS.

Xiang (Shawn) Zhang headshotBiography
Xiang (Shawn) Zhang is a Postdoctoral Associate in the Computational Instrumentation Lab advised by Dr. Brian Anthony. Shawn’s research focuses on non-contact laser ultrasound and design of novel systems to enhance/extend ultrasound beyond present capabilities. Shawn completed his Ph.D. and Master’s at MIT in Mechanical Engineering with research focusing on non-contact ultrasound, including laser ultrasound and ultrasound tomography. Shawn received his undergraduate degree in Mechanical Engineering at the University of Maryland-College Park (UMCP); during which he completed a co-op at National Institute of Standards and Technology (NIST) designing the Watt Balance to redefine the SI kilogram. Outside of research, Shawn was a mentor at MIT MakerWorkshop and a team lead for MIT Hyperloop.