Multiscale photoacoustic microscopy and computed tomography.

Area of Science:

• Biomedical Imaging
• Optical Physics
• Biotechnology

Background:

• Existing high-resolution optical imaging techniques like confocal and two-photon microscopy are limited to shallow depths.
• Photoacoustic tomography (PAT) is an emerging biomedical imaging technology with rapid growth.
• PAT overcomes the depth limitations of purely optical methods by leveraging ultrasound's properties.

Purpose of the Study:

• To highlight the capabilities of photoacoustic tomography (PAT) for in vivo biomedical imaging.
• To explain how PAT achieves high-resolution imaging at depths inaccessible to other optical methods.
• To discuss the potential of PAT in multiscale systems biology research.

Main Methods:

• PAT utilizes the photoacoustic effect, where light absorption generates detectable ultrasound waves.
• PAT indirectly enhances tissue transparency by 100 to 1000 fold through low ultrasonic scattering.
• This technique allows for high-resolution sensing of optical contrast within tissues.

Main Results:

• PAT enables high-resolution functional and molecular imaging at depths beyond the optical transport mean free path (~1 mm in skin).
• The technology achieves significant improvements in effective tissue transparency.
• PAT demonstrates the potential for in vivo imaging across multiple length scales, from subcellular to organ levels.

Conclusions:

• Photoacoustic tomography (PAT) is a rapidly advancing biomedical imaging modality.
• PAT provides a unique solution for deep-tissue, high-resolution optical contrast imaging in vivo.
• The multiscale imaging capability of PAT is valuable for systems biology research.