Physical Characterization of a Wireless Radiotracer Detection System Based on Pixelated Silicon for in Vivo Brain Studies in Freely Moving Rats

BLUPS for the four phenotypic traits studied. Each row corresponds to one individual

A wireless beta-microprobe based on pixelated silicon for in vivo brain studies in freely moving rats

The investigation of neurophysiological mechanisms underlying the functional specificity of brain regions requires the development of technologies that are well adjusted to in vivo studies in small animals. An exciting challenge remains the combination of brain imaging and behavioural studies, which associates molecular processes of neuronal communications to their related actions. A pixelated intracerebral probe (PIXSIC) presents a novel strategy using a submillimetric probe for beta+ radiotracer detection based on a pixelated silicon diode that can be stereotaxically implanted in the brain region of interest. This fully autonomous detection system permits time-resolved high sensitivity measurements of radiotracerswith additional imaging features in freelymoving rats. An application-specific integrated circuit (ASIC) allows for parallel signal processing of each pixel and enables the wireless operation. All components of the detector were tested and characterized. The beta+ sensitivity of the system was determined with the probe dipped into radiotracer solutions.Monte Carlo simulations served to validate the experimental values and assess the contribution of gamma noise. Preliminary implantation tests on anaesthetized rats proved PIXSIC's functionality in brain tissue. High spatial resolution allows for the visualization of radiotracer concentration in different brain regions with high temporal resolution. (Some figures may appear in colour only in the online journal

Physical Characterization of a Wireless Radiotracer Detection System Based on Pixelated Silicon for in Vivo Brain Studies in Freely Moving Rats

An exciting challenge for neuro-physiological investigations remains the combination of brain imaging and behavioral studies, which associates molecular processes of neuronal communications to their related actions. PIXSIC presents novel strategy using a submillimeter pixellated probe for β+ radiotracer detection based on a reverse-biased, high-resistivity silicon diode; This fully autonomous detection system permits local, time resolved measurements of radiotracers in a volume of a few mm3 with the probe dipped into aqueous solutions of [18F] and [11C]. Preliminary implantation tests on a anaesthetized rats proved functionality of the PIXSIC probe in brain tissues. High spatial resolution allows for the visualization of radiotracer concentration in different brain regions with a temporal resolution of less than 2 second