title: Optoacoustic imaging based on the interferometric measurement of surface displacement.
abstract: We present images of tissue phantoms and chicken chorio-allantoic membrane vasculature using a novel optoacoustic tomography technique based on the time-resolved interferometric measurement of laser-induced thermoelastic expansion. Our imaging system is based on a modified Mach-Zehnder interferometer that provides surface displacement measurements with a temporal resolution of 4 ns and a displacement sensitivity of 0.3 nm. The images are reconstructed from surface displacement measurements made at several locations following irradiation of the sample with Q-switched Nd:YAG (lambda=532, 1064 nm) laser pulses using a delay and sum beam-forming algorithm. The images shown demonstrate the ability of our method to provide better than 200-microm lateral and 30-microm axial resolution at depths exceeding ten transport mean free paths in highly scattering in-vitro and in-vivo model systems.
authors.affiliation: University of California, Irvine, Department of Chemical Engineering and Materials Science, Irvine, California 92697-2575, USA.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Carp
authors.forename: Vasan
authors.initials: V
authors.lastname: Venugopalan
mesh_terms: D000162:Acoustics; D000465:Algorithms; D000482:Allantois / Q000033:anatomy & histology / Q000098:blood supply; D000818:Animals; D002642:Chick Embryo; D002823:Chorion / Q000033:anatomy & histology / Q000098:blood supply; D004548:Elasticity; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007368:Interferometry / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D055095:Optics and Photonics; D019047:Phantoms, Imaging; D013499:Surface Properties