# Cross-regional real-time visualization of systemic physiology and dynamics with 3D panoramic photoacoustic computed tomography (3D-PanoPACT)

## TL;DR

3D-PanoPACT is a new imaging system that captures real-time, high-resolution 3D images of whole-body physiology and metabolism.

## Contribution

3D-PanoPACT introduces panoramic photoacoustic computed tomography with improved spatiotemporal resolution and broad field of view for systemic imaging.

## Key findings

- 3D-PanoPACT imaged the whole liver at 25 Hz, enabling extraction of arterial networks.
- The system enabled real-time monitoring of whole-brain vasculatures and hemodynamics in the Circle of Willis.
- 3D-PanoPACT visualized the metabolic pathways of a small-molecule probe across multiple organs.

## Abstract

Non-invasive systemic visualization is crucial in biomedical research. Photoacoustic imaging transcends the optical scattering limitations, capturing optical absorption from deep tissue at high resolution. Nevertheless, the full exploitation of its physical advantages faces challenges due to unsatisfactory field of view (FOV), spatiotemporal resolution, and imaging quality. Here, we demonstrate that 3D panoramic photoacoustic computed tomography (3D-PanoPACT) mitigates these limitations by combining dynamical and functional contrasts, high spatiotemporal resolution, and broad three-dimensional FOV, allowing for visualizing cross-regional dynamics from organ to whole-body level. Leveraging its single-pulse-volumetric imaging capability, 3D-PanoPACT imaged the whole liver at 25 Hz, facilitating the extraction of arterial networks. Real-time monitoring of whole-brain vasculatures and functional hemodynamics induced by pharmacological action and physical stimulation was demonstrated, especially in the Circle of Willis. The dynamic visualization of the whole trunk at 10 Hz further substantiates its capacity for systemic imaging. We tracked the metabolic pathways of a small-molecule probe across multiple organs using 3D-PanoPACT, highlighting its value in whole-body, cross-regional dynamic studies. 3D-PanoPACT, being a potent novel imaging tool, exhibits substantial potential for advancing biotechnology.

This study introduces 3D-PanoPACT, a panoramic photoacoustic imaging system enabling high spatiotemporal-resolution visualization of whole-body dynamics and metabolism, overcoming limitations in speed and field of view for advanced 3D tomography.