Circular array transducer based-photoacoustic/ultrasonic endoscopic imaging with tunable ring-beam excitation

Zhihua Xie; Jiamei Liu; Yaguang Ren; Jiqing Huang; Riqiang Lin; Xiatian Wang; Qingyuan Tan; Shengmiao Lv; Liang Song; Chengbo Liu; Teng Ma; Xiaojing Gong

doi:10.1016/j.pacs.2022.100441

Circular array transducer based-photoacoustic/ultrasonic endoscopic imaging with tunable ring-beam excitation

Photoacoustics. 2022 Dec 21:29:100441. doi: 10.1016/j.pacs.2022.100441. eCollection 2023 Feb.

Authors

Zhihua Xie^{1

2}, Jiamei Liu^{2

3}, Yaguang Ren^{1

2}, Jiqing Huang^{2

3}, Riqiang Lin^{1

2}, Xiatian Wang^{1

2}, Qingyuan Tan^{2

3}, Shengmiao Lv^{1

2}, Liang Song^{1

2}, Chengbo Liu^{1

2}, Teng Ma^{2

3}, Xiaojing Gong^{1

2}

Affiliations

¹ Research Laboratory for Biomedical Optics and Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
² CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
³ Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.

Abstract

Photoacoustic/ultrasound endoscopic imaging is regarded as an effective method to achieve accurate detection of intestinal disease by offering both the functional and structural information, simultaneously. Compared to the conventional endoscopy with single transducer and laser spot for signal detection and optical excitation, photoacoustic/ultrasound endoscopic probe using circular array transducer and ring-shaped laser beam avoids the instability brought by the mechanical scanning point-to-point, offering the dual-modality imaging with high accuracy and efficiency. Meanwhile, considering the complex morphological environments of intestinal tracts in clinics, developing the probe having sufficient wide imaging distance range is especially important. In this work, we develop a compact circular photoacoustic/ultrasonic endoscopic probe, using the group of fiber, lens and home-made axicon, to generate relatively concentrated ring-shaped laser beam for 360° excitation with high efficiency. Furthermore, the laser ring size can be tuned conveniently by changing the fiber-lens distance to ensure the potential applicability of the probe in various and complex morphological environments of intestines. Phantom experimental results demonstrate imaging distance range wide enough to cover from 12 mm to 30 mm. In addition, the accessibility of the photoacoustic signals of molecular probes in ex vivo experiments at the tissue depth of 7 mm using excitation energy of 5 mJ has also been demonstrated, showing a high optical excitation efficiency of the probe.

Keywords: Circular array transducer; Imaging distance; Optical excitation efficiency; PAE/EUS probe; Photoacoustic/ultrasonic endoscopy; Tunable ring-beam.