# A handheld photoacoustic microscopic probe integrating a transparent ultrasound transducer and a fiber scanner

## TL;DR

Researchers created a compact handheld photoacoustic imaging device that enables fast, high-resolution 3D imaging of blood vessels and lymphatics in live animals.

## Contribution

A novel handheld PAM probe integrating a fiber scanner and transparent ultrasound transducer for high-resolution, rapid imaging.

## Key findings

- The probe achieves 7 μm lateral and 47 μm axial resolution with a 2.6 mm field of view.
- It successfully imaged abdominal organs, vascular changes, and lymphatic vessels in live animals.
- The device was used to delineate vascular networks in early metastatic tumors.

## Abstract

Photoacoustic microscopy (PAM) has been widely used in biomedical studies to provide high-resolution 3D anatomical, functional, and molecular images of living subjects. While handheld PAM systems have been proposed to extend its applicability, it has proved challenging to achieve a compact device that combines fast imaging with high spatial resolution and signal to noise ratio. Here we demonstrate a handheld PAM probe integrating a fiber scanner and high-frequency transparent ultrasound transducer (TUT), called hPAM-TUT. The compact system (measuring 17 mm in diameter, with a 90 mm long rigid body) achieves high lateral and axial resolutions (7 and 47 μm, respectively), has a 2.6 mm diameter field of view, and delivers a single volumetric image in 1.5 s. In living rats, we used hPAM-TUT to visualize various abdominal organs, and in mice we used it to observe epinephrine-induced vascular changes and image the anatomy and functioning of lymphatic vessels after injection of Evans blue dye. Additionally, we successfully delineated murine vascular networks in early metastatic tumors. This handheld PAM probe shows promise for both clinical and research applications in such fields as dermatology, oncology, and intraoperative imaging.

The authors develop a handheld photoacoustic probe integrating a fiber scanner and transparent ultrasound transducer. They demonstrate rapid, high-resolution 3D imaging of vessels and lymphatics in living animals, confirming translational potential.