Miniature probe integrating optical-resolution photoacoustic microscopy, optical coherence tomography, and ultrasound imaging: proof-of-concept

Abstract

In this Letter, we present a novel tri-modal miniature side-view probe, through which optical-resolution photoacoustic microscopy (OR-PAM), optical coherence tomography (OCT), and pulse-echo ultrasound (US) images can be coaxially acquired and displayed simultaneously. The probe consists of a common optical path for OR-PAM (light delivery) and OCT (light delivery/detection), and a 40-MHz unfocused ultrasound transducer for OR-PAM (photoacoustic detection) and US (ultrasound transmission/receiving) with an overall diameter of 2 mm. Combining OR-PAM, OCT, and US would provide complementary information including optical absorption (OR-PAM), optical back-scattering (OCT), and deep tissue structures (US) about biological tissue. Based on an integrated imaging system consisting of OR-PAM, time-domain OCT, and US, phantom images and in vivo images of rat ear were acquired to demonstrate the capabilities of the integrated tri-modality imaging probe. The probe yields a lateral resolution of 13.6 μm for OR-PAM and OCT, and an axial resolution of 43 μm for OR-PAM and US. Currently, for a scanning area of 1 ×1 mm, it took ∼25 min to acquire data for tri-modal volumetric imaging.

Wearable scanning photoacoustic brain imaging in behaving rats

“…It has realized ∼0.5 mm lateral and 0.1 mm axial resolutions, and was capable of imaging a target as deep as 11 mm in a phantom sample and blood vessels as deep as ∼5 mm with intact scalp and skull in a behaving rat. Replacing the fiber bundle with a single mode fiber, its lateral resolution could be significantly improved since it would work under optical resolution photoacoustic microscopy (OR‐PAM) mode, in which the lateral resolution primarily depends on the focus of the light . However, its imaging depth would be superficial and it would be difficult to image blood vessels beneath the skull.…”

Endoscopic optical coherence tomography: technologies and clinical applications [Invited]

“…It is anticipated that the probe diameter will be further reduced to facilitate in vivo applications. In addition to OCT-ultrasound dual-modality integration, prototypes of trimodal endoscopes (OCT, ultrasound and photoacoustic) have recently been demonstrated [102,103], enabling simultaneous, multi-resolution, multi-contrast and multi-scale imaging of internal organs. The diagnosis of intravascular disease is possibly the most advanced clinical application space for OCT other than ophthalmology.…”

Co-registered photoacoustic and ultrasound imaging for tongue cancer detection

“…In intravascular and endoscopic research, ultrasound imaging has been extensively combined with di®erent PA imaging modalities such as PA computed tomography, acoustic-resolution PA microscopy and optical-resolution PA microscopy to supplement tissue/organ structures. [21][22][23] During the development of tongue cancer, there exists angiogenesis in the early-stage cancerization of tissues. 24 Angiogenesis will result in a large number of newborn blood vessels serving as strong optical absorption contrast to distinguish cancerous tissues from normal tissues for PA imaging.…”