A camera sub-module is provided for providing tomographic imaging of radiation emissions generated internally by a body. The camera sub-module includes a radiation-emitting layer having a radioactive source for emitting transmission emissions, and at least one radiation-detection layer for contemporaneously detecting and permitting differentiation between the transmission emissions and emissions generated internal to an imaged body administered with a positron-emitting radiotracer. Also provided herein are imaging systems, scanners, and other apparatus and methods.