Author: Quentin Geluyckens

Because it is sensitive to the microscopic displacements of water molecules diffusing in the tissues, diffusion-weighted magnetic resonance imaging (DW-MRI) has become the modality of choice to study the anatomy of the white matter at the micrometer level, with applications in the diagnosis and treatment of many neurological disorders and brain injuries. Our new approach at the intersection of physical modeling, numerical simulations and signal processing proposes a way to bridge the gap between the native millimeter resolution of MRI and neuroanatomical indices at the micrometer scale. We use specific MRI acquisitions known as diffusion-weighted MRI which by design are sensitive to the micrometer-scale diffusing motion of water molecules in the tissues at body temperature. In traditional approaches, forward mathematical models based on analytical formulas are devised to link the geometry of white matter tissue, the diffusion of water molecules in that geometric arrangement and the physics of MRI acquisitions. The free parameters of such a forward model are then adjusted...

ImagX.R, the research group on image guided proton therapy, has the pleasure to announce the PhD defence of Sylvain Deffet. He will present his research on proton radiography and discuss how this method could improve treatment outcome in proton therapy. Proton therapy is an advanced form of radiation therapy which is increasingly used worldwide. Unlike photons, protons deliver a sharp dose at a precise location corresponding to their range in the patient. Thanks to this physical property, proton therapy has the potential to spare healthy tissues better than conventional radiation therapy. However, a consequence of this dosimetric property is that the range of the protons inside the patient must be accurately predicted to deliver the dose as planned. Unfortunately, several uncertainties arising during treatment planning may significantly impact the range of the protons and hence jeopardize dose conformity. To better quantify and potentially reduce the uncertainties, the implementation of imaging techniques that would provide a direct information on the energy reduction...