Quantification of optical absorption coefficient from acoustic spectra in the optical diffusive regime using photoacoustic microscopy
Photoacoustic (PA) tomography (PAT) can image optical absorption contrast with ultrasonic spatial resolution in the optical diffusive regime. Multi-wavelength PAT can noninvasively monitor hemoglobin oxygen saturation (sO_2) with high sensitivity and fine spatial resolution. However, accurate quantification in PAT requires knowledge of the optical fluence distribution, acoustic wave attenuation, and detection system bandwidth. We propose a method to circumvent this requirement using acoustic spectra of PA signals acquired at two optical wavelengths. With the acoustic spectral method, the absorption coefficients of an oxygenated bovine blood phantom at 560 and 575 nm were quantified with errors of <5%.
Additional Information© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). We would like to thank Yan Liu, Dr. Xiao Xu and Dr. Konstantin Maslov for useful discussions and Prof. James Ballard for editing the manuscript. This work was sponsored in part by National Institutes of Health grants R01 EB008085, R01 EB000712, R01 CA134539, R01 CA157277, and U54 CA 136398. L. W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work.
Published - 82234C.pdf