Effect of light scattering on optical-resolution photoacoustic microscopy
The penetration depth of ballistic optical imaging technologies is limited by light scattering. To study the effect of scattering on optical-resolution photoacoustic microscopy (OR-PAM), we divided the signals in OR-PAM into two classes: one is from the target volume defined by the optical resolution cell (Class I); the other is from the rest of the acoustic resolution cell (Class II). We developed a way to simulate the point spread function (PSF) of our OR-PAM system considering both optical illumination and acoustic detection, then used the PSF to calculate the contributions of each class of signal to the total signal at different focal depths. Our simulation results showed that: 1) The Class II signal decays much more slowly than the Class I signal; 2) The full width at half maximum (FWHM) of the PSF for the focal depth of 0.9 transport mean free path (TMFP) is not broadened much (~10%) compared with that for a clear medium; 3) Image contrast is degraded with increasing depth when there is a uniform absorption background.
Additional Information© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). We would like to thank Zijian Guo and Kun Wang for helpful discussions. 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 - 82233S.pdf