Dual-foci fast-scanning photoacoustic microscopy with 3.2-MHz A-line rate

Jiangbo Chen; Yachao Zhang; Songnan Bai; Jingyi Zhu; Pakpong Chirarattananon; Kai Ni; Qian Zhou; Lidai Wang

doi:10.1016/j.pacs.2021.100292

Dual-foci fast-scanning photoacoustic microscopy with 3.2-MHz A-line rate

Photoacoustics. 2021 Aug 9:23:100292. doi: 10.1016/j.pacs.2021.100292. eCollection 2021 Sep.

Authors

Jiangbo Chen¹, Yachao Zhang¹, Songnan Bai¹, Jingyi Zhu¹, Pakpong Chirarattananon¹, Kai Ni², Qian Zhou², Lidai Wang^{1

3}

Affiliations

¹ Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong SAR, China.
² Division of Advanced Manufacturing, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
³ City University of Hong Kong Shenzhen Research Institute, Yuexing Yi Dao, Shenzhen, Guang Dong, 518057, China.

Abstract

We report fiber-based dual-foci fast-scanning OR-PAM that can double the scanning rate without compromising the imaging resolution, the field of view, and the detection sensitivity. To achieve fast scanning speed, the OR-PAM system uses a single-axis water-immersible resonant scanning mirror that can confocally scan the optical and acoustic beams at 1018 Hz with a 3-mm range. Pulse energies of 45∼100-nJ are sufficient for acquiring vascular and oxygen-saturation images. The dual-foci method can double the B-scan rate to 2036 Hz. Using two lasers and stimulated Raman scattering, we achieve dual-wavelength excitation on both foci, and the total A-line rate is 3.2-MHz. In in vivo experiments, we inject epinephrine and monitor the hemodynamic and oxygen saturation response in the peripheral vessels at 1.7 Hz over 2.5 × 6.7 mm². Dual-foci OR-PAM offers a new imaging tool for the study of fast physiological and pathological changes.

Keywords: Dual foci; Fast imaging; Fiber-based; OR-PAM; Resonant scanning.