Photoacoustic probe using a microring resonator ultrasonic sensor for endoscopic applications

Abstract

We designed an all-optical photoacoustic probe for endoscopic applications by employing an optically-transparent, coverslip-type, polymeric micro-ring resonator ultrasonic sensor. We experimentally quantified the axial, tangential, and radial resolutions and angular sensitive stability of this probe. Using this probe, we achieved volumetric imaging of several phantoms. Our all-optical probe design offers clear benefit in integrating photoacoustic endoscope with other optical endoscopic imaging modalities to facilitate the transformation from bench to bedside.

Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging

“…Several methods for detecting ultrasound at the tip of an optical fiber have been explored with those based on interferometry [13][14][15][16] or Bragg grating sensors [17] offering the highest broadband sensitivity. One promising approach exploits the detection of acoustically-induced changes in the reflectance of a polymer Fabry-Pérot (FP) cavity [18,19].…”

Label-free optical-resolution photoacoustic endomicroscopy in vivo

“…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. The spatial resolution is the highest yet reported for optical-resolution endoscopic PA images [57,58].…”

“…As shown in the in vivo and ex vivo image demonstrations, the major benefit of the OR-PAEM over existing IVM techniques [44][45][46][47][48][49][50][51][52][53][54][55][56] lies in its label-free angiographic imaging capability, which provides critical image in experimental biology and clinical medicine. Although other groups [57,58] developed endoscopic devices with optical focusing and achieved an even smaller probe diameter (i.e., ~1.1 mm in the case of ref. 57), their probes, currently not fully encapsulated, cannot be utilized for in vivo IVM.…”

“…Very recently, two research groups reported such endoscopic devices with optical focusing and demonstrated PA images with transverse resolutions of 19.6 µm and 15.7 µm, respectively [57,58]. However, their imaging probes were not fully encapsulated, and thus they could demonstrate the systems by imaging only phantoms, such as a metallic stent.…”

Optical-resolution photoacoustic endomicroscopy in vivo

“…So far, two groups have reported such endoscopic devices with optical focusing and demonstrated PA images with transverse resolutions of 19.6 µm and 15.7 µm, respectively [38,39]. However, the images were all limited to phantom experiments because the imaging probes were not fully encapsulated, which is crucial for IVM applications, especially for internal organ imaging.…”