A positron emission tomography (PET) detector assembly (14) is provided. The PET detector assembly includes a plate (56) having a first side (60) and an opposite second side (62), the plate being fabricated from a thermally conductive material. The PET detector assembly also includes multiple PET detector units (44) coupled to the first side of the plate. The PET detector assembly further includes a readout electronics section (64) coupled to the second side of the plate, wherein, during operation, the readout electronics section generates heat that is transferred to the plate. The plate comprises a heat pipe (108) disposed within the plate and configured to extract the heat from the plate and to transfer the heat away from the plate.