Photoacoustic endomicroscopy based on a MEMS scanning mirror

Abstract

In this Letter, we present a high-resolution photoacoustic endomicroscopy probe based on a microelectromechanical systems (MEMS) scanning mirror. The built-in optical assembly consists of a 0.7 mm graded-index (GRIN) lens for light focusing and a ϕ1 mm MEMS mirror to reflect and scan the beam. A miniaturized unfocused ultrasound transducer with a center frequency of 10 MHz is used for photoacoustic detection. Sharp blades, carbon fibers, and black tapes were utilized to evaluate the performance of the system. In vivo mouse ears and resected rectums were imaged to further demonstrate the feasibility of this probe for potential biological and clinical applications.

Miniature probe for dual‐modality photoacoustic microscopy and white‐light microscopy for image guidance: A prototype toward an endoscope

“…The former is termed as optical‐resolution PAM (OR‐PAM) , and the latter acoustic‐resolution PAM (AR‐PAM) . Over the past few years, many attempts have been made to implement PAM as miniature probes, also called photoacoustic endoscopy (PAE) , which enables PAM of internal organs. PAE is desired for minimally invasive interventional procedures.…”

“…Recently, many PAE applications have been demonstrated, such as gastrointestinal tract , intravascular and urogenital system imaging . Similar to PAM, PAE can be categorized into OR‐PAE and AR‐PAE , also depending on how resolution is determined. OR‐PAE typically employs a single‐mode optical fiber and a gradient‐index (GRIN) lens to provide high resolution up to several micrometers despite sacrificing imaging depth.…”

Wearable optical resolution photoacoustic microscopy

“…Optical resolution photoacoustic microscopy (ORPAM), featuring high spatial resolution, deep penetration depth and large FOV, is a noninvasive and label‐free imaging approach capable of monitoring brain hemodynamics at microscale level . Current developments of ORPAM mainly focus on miniaturization of the device using new scanning mechanisms and optical/acoustic scanners . However, it is challenging to develop a wearable photoacoustic microscope, which enables the investigation of brain activities on a freely moving rodent.…”

Ultracompact high-resolution photoacoustic microscopy

“…During the experiments, the probe utilized the organ fluid as the coupling medium for ultrasound transmission, avoiding potential infection caused by external coupling mediums such as ultrasound gels and water. To date, except for the colon which can be imaged by PA endoscopy [21][22][23], there are no high-resolution PA imaging techniques capable of imaging internal organs with sufficient high resolving ability and FOV. Due to severe angiogenetic phenomena in cancer lesions [24], our probe has the potential to capture primary, residual, and metastatic cancer lesions in various internal organs using minimally invasive surgery in clinic.…”

“…It is known that there are ultrahigh dense vascular networks in the oral cavity, which are tightly associated with numerous diseases such as oral ulcers, oral cancer, and cardiovascular abnormalities in humans [21,25]. We carried out the in vivo imaging of different tissues in the human oral cavity to demonstrate the clinical feasibility of the ultracompact probe in oral disease detection.…”