(a) PA image of wire embedded in ex-vivo liver at 7 cm. (b) PA image of hemoglobin in ex-vivo liver at approximately 2 cm. Magenta spot represents center of fiber, while green, grey, and gold boxes represent kernels for 5.8-mm, 8.1-mm, and 10.4-mm analysis, respectively; dot in center of kernel denotes measurement point (i.e., where distance from the source was measured). (c) Multi-wavelength acquisition (N = 30) of deoxyhemoglobin target at distances of 5.8 mm (green), 8.1 mm (grey), and 10.4 mm (gold) from the inserted fiber tip. (d) Optical absorption spectrum of deoxyhemoglobin [20].