|Gamma camera with parallel collimators|
Principle of gamma detection using a collimator with parallel channels. Only gamma propagating along the channel axis reach the scintillator, where they deposit their energy, generating a brief flash of light. The scintillation is detected by an array of photomultiplier looking at the back of the scintillator. Photomultiplier converts the light pulse into an electronic signal that is amplified by the electronics of the camera. From the signals received by the photomultipliers, the approximate position of the impact and the gamma energy are evaluated. The insert shows a gamma camera pointed at the chest of a patient, probably for a heart scan.