In this chapter, all aspects of SPECT imaging are detailed. Data acquisition and image reconstruction are explained with reference to different SPECT cameras by manufacturers. Backprojrction, filtered backprojection, and iterative reconstruction (MLEM and OSEM) are included in the discussion. Characteristic properties of different SPECT scanners are presented in a table, and their detailed explanation is given. Use of CT scanners in SPECT/CT is added with a description on how it is applied in attenuation correction.