Ponente
Descripción
I will provide an overview of the most famous experimental developments proposed so far with prototypes comprising liquid xenon in order to supplant the solid cameras used today in functional medical PET gamma-rays imaging. A parenthesis also addresses the operating principle of Compton telescopes will be provided in order to motivate their future use in the context of XEMIS (Xenon Medical Imaging System) experiments.
XEMIS2 is a project that uses liquid xenon (LXe) to provide a significant improvement in Small Animal Compton Medical Imaging. Currently being installed at the Nantes hospital (Nantes CHU), the camera is like a small physics experiment containing 200 kg of liquid xenon and its associated infrastructure. The active zone consists of a time projection chamber (single phase liquid xenon TPC) allowing precise measurement of the charge and the light produced by the interaction of high energy gamma-rays. The technology deployed for reading ionization signals is adapted from the principles used by micropattern gaseous detectors, the anodes contain 20000 pixels of 3x3 mm2 sides and the experimental measurement chain is entirely specific. The noise level measured on each of the pixels at room temperature is close to 100 electrons, and we hope thanks to these performances to be able to locate electronic recoils in liquid xenon with a spatial resolution of 100 microns in each of the 3 dimensions.
Thus, thanks to these exceptional technological performances, we plan to produce very good images with very little radioactivity in the field of view by using the principle of Compton imaging, in particular that implemented for the observation of labeled drugs with 44-Scandium emitting 3 photons in quasi spatial and temporal coincidences.
The first images are thus planned with 20 kBq of activity present in the small animal and with an exposure time of 20 mns, the camera should come into operation from the beginning of the year 2024. The complete and specific system of acquisition that has been developed for recorded information will also be presented.
Finally, XEMIS2 is a first demonstrator of the unique capability of experiments containing liquid xenon for Compton medical imaging. The prospects for evolution in order to gradually reach the human scale will also be presented.
