Postdoc position : Numerical simulation for noise-based imaging in heterogeneous and viscoelastic media with application to tumor tissue characterization

UGA offer
  • Employer : Université Grenoble Alpes, Institute of Earth Sciences (https://www.isterre.fr/), Grenoble, France.
  • Type of Contract : Temporary (CDD), Full-time. The hiring is on a yearly basis with the possibility of extension to a total duration of 3 years.
  • Starting Date : as soon as possible in 2024
  • Funding : « PCSI SMART Imaging » in collaboration with LabTau (INSERM-Lyon) and Institut Langevin (Paris)

Offer description

The work is part of a research project on the imaging and characterization of biological tissues. The aim is to add new elements of differentiation between healthy tissue and cancerous tumors, in particular absorption, viscosity or porosity. The first objective is to test the method of local imaging of shear waves, known as "focal spot imaging" in seismology, for highly heterogeneous soft media and in the presence of viscoelasticity. The work will rely on numerical simulation for advanced analysis, which will be compared with experiments carried out by the project partners.

The ’focal spot imaging’ technique consists in creating a focus at a point in depth based on correlation functions between shear deformations measured by ultrasonic speckle analysis at different points around the reference point. A simple theory is established for the case where the medium is perfectly elastic and homogeneous. Extensions are proposed for the presence of absorption.

Numerical simulation should enable us to explore the impact of the presence of wide-spectrum heterogeneities on focusing quality and spot width. The introduction of a more accurate description of the biological environment requires consideration of a two-phase medium in which fluids play an important role. “Porous medium" approaches can be used to assess the effects of wave velocity dispersion and absorption via the viscosity of biological fluids.

The candidate should have a solid grounding in numerical simulation and an interest in working in a multidisciplinary group. He or she will have to interact with teams from different backgrounds. A background in geophysical or medical imaging, or in applied mathematics will be appreciated.

Contact information :

Michel Campillo, professeur émérite, ISTerre, michel.campillo univ-grenoble-alpes.fr
Ludovic Métivier, CR CNRS, ISTerre/LJK, ludovic.metivier univ-grenoble-alpes.fr
Romain Brossier, maitre de conférence, ISTerre, romain.brossier univ-grenoble-alpes.fr