ClearPEM is a unique dual-head Positron Emission Mammography (PEM) scanner using APD-based detector modules with the capability of measuring depth-of-interaction (DOI) with a resolution of 2 mm within very dense Cerium doped Lutetium-Yttrium oxy-orthosilicate scintillating crystals (LYSO:Ce). These specifications make it possible for the detection of 3 mm breast lesions in less than 7 minutes exams, thanks to the image spatial resolution of 1.2 mm and to the high sensitivity of the detector device. The full system comprises 192 detector modules in a total of 6144 LYSO:Ce crystals and 384 32-pixel APD arrays arranged in two detector plates rotating around the breast encompassed with a cone applying minimum compression. The patient is installed on a table in prone position with hanging breast. A first prototype of the ClearPEM has been built by a Portuguese consortium in the framework of Crystal Clear. This system is installed in the hospital of Coimbra, Portugal for a clinical validation. A second prototype has been built and installed in Hospital Nord in Marseille, France (see ClearPEM Sonic).