Double-Clad Optical Fiber-Based Multi-Contrast Noncontact Photoacoustic and Fluorescence Imaging System

Jun Geun Shin,Jonghyun Eom

doi:10.3390/electronics10233008

Abstract

A noncontact photoacoustic and fluorescence dual-modality imaging system is proposed, which integrates a fiber-based fluorescence imaging system with noncontact photoacoustic imaging using a specially fabricated double-cladding fiber (DCF) coupler and a DCF lens. The performance of the DCF coupler and lens was evaluated, and the feasibility of this new imaging system was demonstrated using simple tubing phantoms with black ink and fluorophore. Our imaging results demonstrated that the multimodal imaging technique can simultaneously acquire photoacoustic and fluorescence images without coming into contact with the sample. Consequently, the developed method is the first noncontact scheme among multimodal imaging systems that is integrated with a photoacoustic imaging system, which can provide varied and complementary information about the sample.

Highlights

Multi-contrast images can be used to quantify or classify samples more effectively because they contain morphological, functional, and molecular information about the same biological specimens [1]
To provide a more comprehensive understanding of physiological processes in biological samples, the photoacoustic imaging (PAI) system has been integrated with optical imaging modalities such as fluorescence imaging (FLI) [7,8], diffuse optical tomography, optical coherence tomography (OCT) [2,3,9,10,11,12], and fluorescence confocal microscopy
To overcome these limitations while developing a multimodal PAI system, multimodal imaging techniques using noncontact PAI have been studied [15,16], which can be combined with other optical imaging devices by measuring ultrasonic signals using a noncontact method [10,11,12,17]. ncPAI detects the vibrations of the sample surface that are induced by photoacoustic waves generated inside the sample by using optical interference, which does not require the use of a coupling agent for ultrasonic impedance matching

Summary

Introduction

Multi-contrast images can be used to quantify or classify samples more effectively because they contain morphological, functional, and molecular information about the same biological specimens [1]. It is fundamentally difficult to integrate PAI into a common path with an optical detection regime that is based on an optical imaging modality (fluorescence imaging) This is because, to effectively measure ultrasonic signals, PAI requires an ultrasonic transducer to be in close contact with the sample surface, as well as an ultrasonic impedance matching process. NcPAI detects the vibrations of the sample surface that are induced by photoacoustic waves generated inside the sample by using optical interference, which does not require the use of a coupling agent (water or gel) for ultrasonic impedance matching This noncontact optical ultrasound detection can be and configured with other optical imaging techniques and a common path of light irradiation, resulting in an configurable multimodal imaging system that can generate co-registered images without any image processing. The proposed method simultaneously acquires both photoacoustic and fluorescence images without coming into contact with the sample, which shows that varied and complementary information about the sample can be obtained

Materials and Methods

Noncontact Combined PA and Fluorescence Imaging System

Optical Interferometry for Noncontact Fiber-based PA imaging

Fiber-Based Fluorescence Imaging System

PA Imaging and Fluorescence Imaging Performance

Conclusions