Background

Photoacoustic imaging is a powerful tool in biological and pre-clinical applications. It combines the advantages of the excellent optical contrast from optical imaging and the deep penetration depth of ultrasound imaging. Photoacoustic imaging is widely used in studies such as imaging the blood oxygenation, vasculature, and skin anomalies [1-3].

Motivation

When the tissue is irritated by a short laser pulse, light propagates inside the tissue and a light fluence map is generated. The spatial distribution of the fluence is governed by the photon transport process which is closely related to the optical properties inculding absorption and scattering of the tissue. Precise calculation of the light fluence map will greatly improve the quality of the following photoacoustic image.

Tasks

The student will

• read reviews of photoacoustic imaging to have an overview of the modality and a good understanding of its physical principles
• read selected literature on different light fluence calculation methods, understand how they work and they pros and cons
• get familiar with the existing diffusion model, explore its limitations
• propose and implement new methods to precise calculate the fluence for heterogeneous tissues at different depths

References:

• Image credit: M. Kirillin, V. Perekatova, I. Turchin, and P. Subochev, “Fluence compensation in raster-scan optoacoustic angiography,” Photoacoustics, vol. 8, pp. 59–67, Dec. 2017.
• [1] M. Omar, J. Aguirre, and V. Ntziachristos, “Optoacoustic mesoscopy for biomedicine,” Nat Biomed Eng, vol. 3, no. 5, pp. 354–370, May 2019.
• [2] H. He et al., “Fast raster-scan optoacoustic mesoscopy enables assessment of human melanoma microvasculature in vivo,” Nat Commun, vol. 13, no. 1, p. 2803, Dec. 2022.
• [3] M. Li, Y. Tang, and J. Yao, “Photoacoustic tomography of blood oxygenation: A mini review,” Photoacoustics, vol. 10, pp. 65–73, Jun. 2018.