A positron emission tomography (PET) detector configuration for a combined PET and computed tomography (CT) imaging system, wherein the CT system includes an annular cavity. The configuration includes a backplane having a neutral axis and an aperture. In addition, the configuration includes at least one PET detector located about the aperture, wherein a center of mass of the at least one PET detector is in-line with the neutral axis and wherein a portion of the at least one PET detector is located in the annular cavity thereby reducing a footprint of the combined PET and CT imaging system. Further, the location of the at least one PET detector reduces the strength needed for maintaining structural integrity of the backplane.