  We present first results from a Positron Emission Tomography (PET) scanner
demonstrator based on Resistive Plate Chambers and specialized for brain
imaging. The device features a 30 cm wide cubic field-of-view and each detector
comprises 40 gas gaps with 3D location of the interaction point of the photon.
Besides other imagery, we show that the reconstructed image resolution, as
evaluated by a hot-rod phantom, is sub-millimetric, which is beyond the
state-of-the-art of the standard PET technology for this application.
