Work

Simultaneous estimation of electrical conductivity and permittivity in quantitative thermoacoustic tomography

Year: 2025

Type: article

Abstract: In this work, the inverse problem of quantitative thermoacoustic tomography is studied. In quantitative thermoacoustic tomography, dielectric parameters of an imaged target are estimated from an absorbed energy density induced by an externally introduced electromagnetic excitation. In this work, simultaneous estimation of electrical conductivity and permittivity is considered. We approach this problem in the framework of Bayesian inverse problems. The dielectric parameters are estimated by computing maximum a posteriori estimates, and the reliability of the estimates is studied using the Laplace’s approximation. The forward model to describe electromagnetic wave propagation is based on a vectorial Maxwell’s equation, that is numerically approximated using a finite element method with edge elements. The proposed methodology is evaluated using numerical simulations utilising one or two electromagnetic excitations at multiple excitation frequencies. The results show that the electrical conductivity and permittivity can be simultaneously estimated in quantitative thermoacoustic tomography. However, the problem can suffer from non-uniqueness, which could be overcome using multiple electromagnetic excitations.

Source: Inverse Problems

DOI: 10.1088/1361-6420/adb98d

Authors: Teemu Sahlström, Timo Lähivaara, Tanja Tarvainen

Institution: University of Eastern Finland

Language: English

Topic: Photoacoustic and Ultrasonic Imaging

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,325

Funders: European Commission, Academy of Finland, China Scholarship Council, European Research Council