An imaging system for obtaining images of a patient comprises a first scanning device, for example a CT scanner or an MRI scanner, and a second scanning device, being a SPECT scanner device. A mover mechanism moves a patient carrier in a first direction into the first imaging space of the first scanning device. The SPECT scanner device is positioned behind the first scanning device. The mover mechanism moves the patient carrier further in the first direction into the SPECT imaging space. The SPECT scanner device comprises a housing accommodating a set of detectors. The imaging system further comprises a plurality of exchangeable collimator assemblies with a first and a second collimator assembly, said assemblies having different imaging properties. The SPECT scanner device is configured for removal and introduction of each one of said plurality of exchangeable collimator assemblies at a side of the housing thereof that faces away from the first scanning device. A collimator support and conveyance system is configured to support and convey each collimator assembly in replacing one of the plurality of exchangeable collimator assemblies that is positioned in the SPECT scanner around the SPECT imaging space for another one of the plurality of exchangeable collimator assemblies.
