An All-Fiber-Optic Combined System of Noncontact Photoacoustic Tomography and Optical Coherence Tomography.

Jonghyun Eom,Sunghwan Rim,Byeong Lee,Soongho Park,Jun Shin

doi:10.3390/s16050734

Abstract

We propose an all-fiber-based dual-modal imaging system that combines noncontact photoacoustic tomography (PAT) and optical coherence tomography (OCT). The PAT remotely measures photoacoustic (PA) signals with a 1550-nm laser on the surface of a sample by utilizing a fiber interferometer as an ultrasound detector. The fiber-based OCT, employing a swept-source laser centered at 1310 nm, shares the sample arm of the PAT system. The fiber-optic probe for the combined system was homemade with a lensed single-mode fiber (SMF) and a large-core multimode fiber (MMF). The compact and robust common probe is capable of obtaining both the PA and the OCT signals at the same position without any physical contact. Additionally, the MMF of the probe delivers the short pulses of a Nd:YAG laser to efficiently excite the PA signals. We experimentally demonstrate the feasibility of the proposed dual-modal system with a phantom made of a fishing line and a black polyethylene terephthalate fiber in a tissue mimicking solution. The all-fiber-optic system, capable of providing complementary information about absorption and scattering, has a promising potential in minimally invasive and endoscopic imaging.

Highlights

Photoacoustic tomography (PAT) is a powerful noninvasive and nonionizing biomedical imaging modality that has attracted great attention in the last decade [1,2,3,4]
photoacoustic tomography (PAT)-optical coherence tomography (OCT) system system is is depicted depicted in configuration is based on two fiber-based
The proposed all-fiber-based PAT and OCT system can be used for the dual-modal endoscopy imaging owing to its compactness

Summary

Introduction

Photoacoustic tomography (PAT) is a powerful noninvasive and nonionizing biomedical imaging modality that has attracted great attention in the last decade [1,2,3,4]. PAT is based on the optical absorption and detects laser-induced ultrasound waves via the photoacoustic (PA) effect [5]. When a short pulse from a laser illuminates a biological sample, a portion of the laser energy is absorbed in chromophores such as hemoglobin, melanin, etc. Since the PA signal is strongly associated with the optical absorption properties of the sample, PAT can provide optically absorbed structural (i.e., vascular structure and internal organs), functional (blood oxygen concentration, blood flow, and hemodynamic change), and molecular (tumor and cancer cell) images of various biological tissues [1,2,3,4]. PAT is capable of enhanced depth imaging compared with the traditional optical imaging modalities

Methods

Discussion

Conclusion