Projects

The collaborative project comprises four thematically organised subprojects.

Two methodological subprojects study the joint estimation of motion and kinetic parameters using two different mechanical models. A Lagrangian model focuses on the deformation from a reference state (atlas), the central unknown in the inverse problem. An Eulerian model focuses primarily on motion velocity. The key conceptual difference is how prior information is incorporated when regularising the deformation or velocity. The Lagrangian model is more closely aligned with MR acquisition, in which successive slices are recorded over time; the Eulerian model is better suited to time-continuous measurements such as list-mode PET. Alternative imaging modalities may also motivate hybrid methods.

A further methodological subproject studies the selection of regularisation parameters and the quantification of statistical uncertainty, making its results available to the other projects. A mathematically grounded choice of parameters for motion, kinetics, and possibly reconstructed images is a central new aspect. Rather than relying on common heuristics, the project systematically quantifies statistically significant changes in dynamics.

Although mathematics is at the centre of the project, applying the developed methods is also a key objective. The largest, cross-site subproject, TP4, addresses this by covering data management, specialised implementations for available modalities (PET, MR, PET/CT, and PET/MR), and validation.

A smaller coordination project organises collaboration, communication, and the long-term perspective towards drug development.