All-optical optoacoustic micro-tomography in refl ection mode

High-resolution optoacoustic imaging at depths beyond the optical diffusion limit is conventionally performed using amicroscopy setup where a strongly focused ultrasound transducer samples the image object point-by-point. Althoughrecent advancements in miniaturized ultrasound detectors enables one to achieve microscopic resolution with an unfocuseddetector in a tomographic configuration, such an approach requires illuminating the entire object, leading to an inefficientuse of the optical power, and imposing a trans-illumination configuration that is limited to thin objects. We developed anoptoacoustic micro-tomography system in an epi-illumination configuration, in which the illumination is scanned withthe detector. The system is demonstrated in phantoms for imaging depths of up to 5 mm and in vivo for imaging thevasculature of a mouse ear. Although image-formation in optoacoustic tomography generally requires static illumination,our numerical simulations and experimental measurements show that this requirement is relaxed in practice due to lightdiffusion, which homogenizes the fluence in deep tissue layers. KCI Citation Count: 0