title: Laser speckle imaging based on photothermally driven convection.
abstract: Laser speckle imaging (LSI) is an interferometric technique that provides information about the relative speed of moving scatterers in a sample. Photothermal LSI overcomes limitations in depth resolution faced by conventional LSI by incorporating an excitation pulse to target absorption by hemoglobin within the vascular network. Here we present results from experiments designed to determine the mechanism by which photothermal LSI decreases speckle contrast. We measured the impact of mechanical properties on speckle contrast, as well as the spatiotemporal temperature dynamics and bulk convective motion occurring during photothermal LSI. Our collective data strongly support the hypothesis that photothermal LSI achieves a transient reduction in speckle contrast due to bulk motion associated with thermally driven convection. The ability of photothermal LSI to image structures below a scattering medium may have important preclinical and clinical applications.
authors.affiliation: University of California-Irvine, Department of Biomedical Engineering, 3120 Natural Sciences II, Irvine, California 92697, United StatesbBeckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612, United States.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Regan
authors.affiliation: University of California-Irvine, Department of Biomedical Engineering, 3120 Natural Sciences II, Irvine, California 92697, United StatesbBeckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, California 92612, United StatescUn.
authors.forename: Bernard
authors.initials: B
authors.lastname: Choi
mesh_terms: D000818:Animals; D001790:Blood Physiological Phenomena; D018481:Convection; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007368:Interferometry / Q000379:methods*; D007834:Lasers; D019047:Phantoms, Imaging; D011817:Rabbits; D013696:Temperature; D014025:Titanium
chemical_list: C009495:titanium dioxide; D014025:Titanium