Institut Fresnel

These methodological developments concern the evolution from a mono-parametric molecular imaging (mono-modal measurement of the maximum uptake of a single radiotracer administered under basal conditions), to a multidimensional biomedical imaging, based on the extraction and multivariate integration of parameters taking into account multimodality, the multi-tracer approach, and spatial (texture heterogeneities) and temporal dimensions. The latter constitutes an opportunity to develop a per-procedure molecular imaging characterizing, in real time and in the absence of limitations associated with MRI, the physiological or pathological processes, for example to image the dynamic effects of neuro-modulation (transcutaneous magnetic or deep electrical), or to image brain activations requiring complex interaction paradigms, especially in virtual or augmented reality, possibly carried out remotely from the acquisition (outside the instrument) using the specific pharmacokinetic characteristics of radiotracers. Dynamic acquisitions also provide an opportunity to develop and study metabolic brain connectivity, and to extend this approach to molecular biomarkers other than glucose. The improvement of the temporal resolution of dynamic PET acquisitions is mainly conducted by optimizing radiotracer administration protocols, and in particular the modeling of continuous administration. Finally, methodological collaborations concern digital reconstruction, in particular to improve the spatial resolution of PET images by modeling the path of the positron before annihilation; and to improve the signal-to-noise ratio of PET images with few photons (dynamic acquisition, low-dose injection for screening and more systematic monitoring, especially in pediatrics).