Abstract: The invention relates to a detector module (1) for a Positron Emission Tomograph (PET) and for Single Photon Emission Computed Tomography (SPECT) comprising a matrix (3) of scintillator crystals, said matrix having a first side and a second side opposite to said first side, each scintillator crystal having a first end (14) and a second end (15), said scintillator crystals (2) being oriented parallel to each other, whereby said first end (14) and said second end (15) of each of said scintillator crystals (2) coincide with said first side and said second side of said matrix (3), respectively; a first light sensitive detector (6) producing electrical signal proportional to the amount of light detected, being optically connected to said first side of said matrix (3), said first light sensitive detector (6) being position sensitive; and a second light sensitive detector (7) producing electrical signal proportional to the amount of light detected, said second light sensitive detector (7) being optically connected t