Patent ID: 6521893
Filing Date: 2003-02-18
Classification: A61B

Abstract:
In a positron emission tomography (PET) scanner using a scintillation detector wherein the scintillation detector has a scintillation crystal and a plurality of photomultiplier tubes and a pair of coincident gamma events due to an annihilation of a position are detected by the scintillation detector in order to locate the positron emission, an apparatus for identifying said coincident gamma events, the apparatus comprising:a photomultiplier tube for generating a photomultiplier tube signal when a gamma event occurs; an analog-to-digital converter for digitising the photomultiplier tube signal; a clock for generating a clock signal providing a time stamp for the photomultiplier tube signal; and means for generating an encoded signal using the digitised photomultiplier tube signal and the clock signal, the encoded signal using the digitised photomultiplier tube signal and the clock signal, the encoded signal comprising an encoded photomultiplier tube signal followed by an encoded time stamp; wherein, in a subsequent event positioning process, photomultiplier tube signals caused by coincident gamma events are identified by means of the encoded time stamp and the identified encoded signals are utilized for positioning the gamma events.