Effect of ultrasound transducer face reflectivity on the light fluence inside a turbid medium in photoacoustic imaging.
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.
Tavakoli
Behnoosh
B
University of Connecticut, Department of Electrical and Computer Engineering, Storrs, Connecticut 06269, USA.
Kumavor
Patrick D
PD
Aguirre
Andres
A
Zhu
Quing
Q
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
Clin Exp Rheumatol. 2009 Mar-Apr;27(2):387-8
19473590
Opt Lett. 1998 Apr 15;23(8):648-50
18084605
J Biomed Opt. 2009 Sep-Oct;14(5):054014
19895116
Opt Express. 2009 Jun 22;17(13):10489-98
19550444
Opt Lett. 2007 Oct 15;32(20):3002-4
17938680
Appl Opt. 2009 Jun 10;48(17):3204-11
19516366
Opt Lett. 2005 Mar 15;30(6):625-7
15791997
Med Phys. 2008 Dec;35(12):5758-67
19175133
IEEE Trans Med Imaging. 2005 Apr;24(4):436-40
15822801
J Biomed Opt. 2008 Mar-Apr;13(2):024007
18465970
Opt Express. 2007 Mar 19;15(6):3291-300
19532570
J Opt Soc Am A Opt Image Sci Vis. 1994 Oct;11(10):2727-41
7931757
Med Phys. 1999 Sep;26(9):1832-7
10505871
Comput Methods Programs Biomed. 1995 Jul;47(2):131-46
7587160
Nat Biotechnol. 2003 Jul;21(7):803-6
12808463