Photoacoustic endoscopy

Abstract

We have developed photoacoustic endoscopy with a miniaturized imaging probe. A light-guiding optical fiber, an ultrasonic sensor, and a mechanical scanning unit are integrated to enable circumferential sector scanning, which produces B-scan images. Biological tissues, including the gastrointestinal tract of a rat, have been imaged ex vivo or in situ.

Non-restrained measurement of Young's modulus for soft tissue using a photoacoustic technique

“…Recently, Yang et al developed an endoscopic embodiment for ex vivo PA elastography. 6 However, their technique cannot quantitatively evaluate elastic properties.…”

Label-free optical-resolution photoacoustic endomicroscopy in vivo

“…We emphasize that full probe encapsulation is the most critical requirement for minimally-invasive clinical IVM imaging. In this study, by combining the OR-PAM concept [1] with our established probe fabrication technique [36][37][38][39], we successfully implemented the first in vivo OR-PAEM system with full endoscopic imaging functionality.…”

“…We designed the OR-PAEM probe [ Fig. 1(a)] based on the scanning mirror and built-in micromotor-based mechanical scanning mechanism reported in our previous papers [36][37][38][39]. The built-in scanning mechanism provides much better scanning stability than a flexible shaftbased proximal actuation mechanism [43].…”

“…1(b)], the configuration of the confocal optical illumination and acoustic detection [ Fig. 1(c)], and the acoustic matching and sheathing methods were also similar to previous acoustic-resolution (AR) PAE probes [36][37][38][39]. However, to realize OR-PAEM imaging, we implemented the optical illumination unit with optical focusing capability.…”

“…with focused US ring transducer-based optical illumination and an acoustic detection unit, and installed them in a small diameter imaging probe with a mechanical scanning mechanism. We solved the probe encapsulation and acoustic matching requirements by adopting a related strategy utilized in our earlier works [36][37][38][39]. To demonstrate the new imaging probe's in vivo imaging ability, we imaged the descending colons of two rats and acquired the first in vivo OR-PAEM image.…”