| Neurosciences would greatly benefit from the combined use of rodent models with neuroimaging methods that are specifically adapted for the rodent brain. Besides magnetic resonance imaging (MRI) and functional MRI, positron-emission tomography (PET) remains a unique methodology to study in vivo brain processes. However, current high spatial resolution tomographs suffer from several technical limitations when applied to neurosciences, such as low sensitivity, and the need of animal restraining during image acquisition. To complement these limits, we propose a miniaturized and fully autonomous positron sensitive intracerebral telemetric probe to perform in vivo analysis on awake and freely moving animals with high sensitivity, no stress induced during acquisition, and imaging capabilities. The development of this new probe takes advantage of pixellated Si sensor technology to conceive a detector sufficiently miniaturized to be entirely worn by the rodent during the experiment. The system consists of a head-socket with a 200 μm thick Si sensor, on which are integrated 10 pixels of 200 μm x 500 μm. The head-set is connected to a back-board that includes the wireless communication and power supply. The data is transmitted to a RF receiver and PC. Here we present the design of the probe and first trials with its subsystems. Theoretical approaches carried out by Monte-Carlo simulations and Silvaco TCAD led us to design 200 μm thick Si sensors having specific configurations of guard rings and pixels links to guarantee the electrical isolation of the pixels and to allow its electronic stabilization. The Si sensors and associated electronics are currently characterized using both sharp points and specific radioactive phantoms. First implantation tests performed on rats and a strategy to protect brain tissue and probe are also under progress. We will conclude by presenting the coming work program and potential future applications of such probe. |
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