Quantitative photoacoustic microscopy of optical absorption coefficients from acoustic spectra in the optical diffusive regime.
Photoacoustic (PA) microscopy (PAM) can image optical absorption contrast with ultrasonic spatial resolution in the optical diffusive regime. Conventionally, accurate quantification in PAM requires knowledge of the optical fluence attenuation, acoustic pressure attenuation, and detection bandwidth. We circumvent this requirement by quantifying the optical absorption coefficients from the acoustic spectra of PA signals acquired at multiple optical wavelengths. With the acoustic spectral method, the absorption coefficients of an oxygenated bovine blood phantom at 560, 565, 570, and 575 nm were quantified with errors of <3%. We also quantified the total hemoglobin concentration and hemoglobin oxygen saturation in a live mouse. Compared with the conventional amplitude method, the acoustic spectral method provides greater quantification accuracy in the optical diffusive regime. The limitations of the acoustic spectral method was also discussed.
Washington University, Department of Biomedical Engineering, Optical Imaging Laboratory, 1 Brookings Drive, Saint Louis, Missouri 63130, USA. lhwang@wustl.edu
Zijian
Z
Guo
Christopher
C
Favazza
Alejandro
A
Garcia-Uribe
Lihong V
LV
Wang
D000162:Acoustics; D000465:Algorithms; D000818:Animals; D002417:Cattle; D003952:Diagnostic Imaging / Q000379:methods; D004058:Diffusion; D004867:Equipment Design; D006454:Hemoglobins / Q000378:metabolism; D051379:Mice; D008853:Microscopy / Q000379:methods*; D015233:Models, Statistical; D055095:Optics and Photonics; D010100:Oxygen / Q000378:metabolism; D019047:Phantoms, Imaging; D061088:Photoacoustic Techniques / Q000379:methods*; D013053:Spectrophotometry / Q000379:methods
D006454:Hemoglobins; D010100:Oxygen