Portable optical resolution photoacoustic microscopy (pORPAM) for human oral imaging

Abstract

Optical resolution photoacoustic microscopy (ORPAM) represents one of the fastest evolving optical microscopic techniques. However, due to the bulky size and complicated system configuration of conventional ORPAM, it is largely limited to small animal experiments. In this Letter, we present the design and evaluation of a portable ORPAM with a high spatiotemporal resolution and a large field of view. In this system, we utilize a rotatory scanning mechanism instead of the conventional raster scanning to achieve translationless imaging of the probe/samples, making it accessible to the human oral lip and tongue. After phantom evaluation, we applied this system to monitor longitudinal neo-angiogenesis of tumor growth and, for the first time, to the best of our knowledge, image the oral vascular network of humans to show its potential in clinical detection of early-stage oral cancer.

In vivo study of rat cortical hemodynamics using a stereotaxic‐apparatus‐compatible photoacoustic microscope

“…This discrepancy is mainly caused by the unflatten MEMS scanner surface and mismatch of reflective indexes among air, glass and water in the light path. As shown in Figure C, the FWHM of the Gaussian‐fitted axial profile of a typical depth‐resolved PA signal is ~104 μm, which agrees well with the theoretical axial resolution (105 μm) calculated using the given center frequency and bandwidth of the transducer .…”

“…Figure A,B shows the photoacoustic maximum amplitude projection (MAP) image and the corresponding Gaussian‐fitted profile of the imaged blade edge indicated by the red dashed line, respectively. We derives the line spread function (LSF) and calculating the full width at half maximum (FWHM) of the LSF, which is 3.8 μm and represents the experimental lateral resolution of the system . The theoretical lateral resolution, which depends on the numerical aperture of doublet lens, is 3.2 μm.…”

“…Photoacoustic microscopy, especially optical resolution photoacoustic microscopy (ORPAM), has been extensively applied in studying cortical hemodynamic in animals due to the excellent sensitivity to endogenous hemoglobin inside blood vessels, comparable penetration depth with 2/multiphoton microscopy, and identical resolving capability with pure optical microscopies . The use of new scanner and fast laser sources promotes the development of compact and miniaturized ORPAMs, which are suitable for brain imaging and reveal the potential to carry out studies in awaking animals . Unfortunately, none of them is compatible with stereotaxic apparatuses, which are widely used in brain operations from animals to humans due to the bulky size and innegligible weight.…”

Photoacoustic assessment of hemodynamic changes in foot vessels

“…It can afford high resolution images in deep tissue based on optical absorption. PAT has shown its ability in breast cancer [21][22][23], thyroid cancer [24,25], vascular examination [4,[26][27][28][29], inflammatory arthritis and osteoarthritis [30][31][32], oral cancer [33][34][35], bone pathology [36] and dermatology [37][38][39] in human studies. PAT of vasculature can be achieved because hemoglobin is concentrated in blood vessels with strong optical absorption.…”

Quantitative investigation of vascular response to mesenteric venous thrombosis using large‐field‐of‐view photoacoustic microscopy

“…However, limited by the conventional raster scanning mechanism, existing ORPAMs suffers from relative translation between imaging interface and the sample as well as subcentimeter FOV . To solve these issues, we proposed a rotary‐scanning mechanism and developed a large‐field‐view ORPAM (L‐ORPAM), which is free of relative translation, and owns a FOV of 40 mm in lateral and 12 mm in axial . In our previous study, we successfully demonstrated the imaging of mesenteric vasculature in rats with a high lateral resolution of 11.2 μm and a temporal resolution of 0.02 volume per second .…”