title: Effect of ultrasound transducer face reflectivity on the light fluence inside a turbid medium in photoacoustic imaging.
abstract: Many endoscopic, intravascular, and transvaginal applications require light to be delivered through optical fibers in a reflection mode. For photoacoustic imaging in reflection geometry, the front-face reflectivity of the ultrasound transducer face imposes a boundary condition that affects the light fluence and its distribution inside a turbid medium. Understanding and characterizing this boundary condition is critical for maximizing tissue illumination and therefore the signal-to-noise ratio of the photoacoustic signal. We systematically analyze the light fluence under three typical commercial transducer faces having reflection coefficients of 1.4, 18, and 28%, and compare the results to a transducer face with 60% coefficient at the laser wavelength of 750 nm. Monte Carlo simulations and experimental results show that light fluence and distribution obtained inside a turbid medium with the use of the 60% reflection coefficient transducer face has a significant improvement over the others, especially at shallower depths.
authors.affiliation: University of Connecticut, Department of Electrical and Computer Engineering, Storrs, Connecticut 06269, USA.
authors.forename: Behnoosh
authors.initials: B
authors.lastname: Tavakoli
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Kumavor
authors.forename: Andres
authors.initials: A
authors.lastname: Aguirre
authors.forename: Quing
authors.initials: Q
authors.lastname: Zhu
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D033401:Microscopy, Acoustic / Q000295:instrumentation*; D009391:Nephelometry and Turbidimetry / Q000295:instrumentation*; D012542:Scattering, Radiation; D014159:Transducers
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