1. A nuclear camera system comprising: a first detector and a second detector for detecting scintillation events, said first detector and said second detector coupled to an acquisition computer system; a input mechanism for selecting between a PET imaging mode and a SPECT imaging mode; a switchable trigger detection unit that is automatically switchable between coincidence detection when said PET imaging mode is selected and non-coincidence detection when said SPECT imaging mode is selected; said switchable trigger detection unit coupled to supply a first valid event trigger signal to said first detector causing said first detector to record a scintillation event and coupled to supply a second valid event trigger signal to said second detector causing said second detector to record a scintillation event.