Mapping blood vessels and oxygenation throughout the whole mouse brain with dual-frequency fiber-array photoacoustic computed tomography.

A new all‑optical photoacoustic tomography system captures both low‑ and high‑frequency photoacoustic signals using an arc‑shaped fiber array. The high‑frequency channel resolves cortical vessels as fine as 70 μm near the surface; the low‑frequency channel reaches 1.2 cm to image the entire mouse brain. With ultrahigh sensitivity and blood oxygen saturation mapping, this dual‑frequency design alleviates the classic trade‑off between resolution and penetration-offering high‑resolution surface imaging and deep, wide‑field coverage within a single imaging platform.