Prospective Respiration-Gated Photoacoustic Microscopy.

OBJECTIVE: Photoacoustic microscopy (PAM) is a promising biomedical imaging technique that relies on sequential excitation to generate three-dimensional images. It combines the high contrast of optical imaging with high penetration depth of ultrasound imaging. The normal respiration rate of mice is greater than 3 Hz, which leads to motion artifacts in most reported PAM for in vivo imaging. METHODS: Here, we introduce a prospective respiratory gating (PRG) method for PAM to address this problem. We captured the mouse's respiratory signal with a laser displacement sensor, and the photoacoustic signal was acquired at specific phase points of the respiratory signal. The scanning mode and the scanning timing were also designed and evaluated. We combined this method with our PAM to demonstrate its feasibility. RESULTS: Our experiments show that the proposed method can help remove motion artifacts well, and the subcutaneous vascular imaging results of the mouse abdominal region with PRG are much better than those without any gating.