The feasibility of using center frequency spectra in photoacoustic imaging for tissue characterization

In photoacoustic imaging, the amplitude of the photoacoustic signal is used for mapping the spatial distribution of a chromophore in the body and few studies have focused on the potential of using frequency content of the photoacoustic data. This study investigates the feasibility of using the photoacoustic center frequency spectrum in differentiating microspheres of various sizes and colors in phantoms. The microspheres with colors of green and blue, and the same size showed different center frequency spectrum shapes while keeping the offset (mean frequency) approximately the same. In addition, smaller microspheres showed higher center frequency offset, while larger microspheres showed smaller offset, suggesting the potential to use the center frequency spectrum for differentiating chromophores of various optical properties in the body.