Miniature all-optical flexible forward-viewing photoacoustic endoscopy probe for surgical guidance

Abstract

A miniature flexible photoacoustic endoscopy probe that provides high-resolution 3D images of vascular structures in the forward-viewing configuration is described. A planar Fabry–Perot ultrasound sensor with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>3</mml:mn> </mml:mrow> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">d</mml:mi> <mml:mi mathvariant="normal">B</mml:mi> </mml:mrow> </mml:mrow> </mml:math> bandwidth of 53 MHz located at the tip of the probe is interrogated via a flexible fiber bundle and a miniature optical relay system to realize an all-optical probe measuring 7.4 mm in outer diameter at the tip. This approach to photoacoustic endoscopy offers advantages over previous piezoelectric based distal-end scanning probes. These include a forward-viewing configuration in widefield photoacoustic tomography mode, finer spatial sampling (87 µm spatial sampling interval), and wider detection bandwidth (53 MHz) than has been achievable with conventional ultrasound detection technology and an all-optical passive imaging head for safe endoscopic use.