System and method for calibrating a PET scanner

A method for calibrating a PET scanner, the PET scanner having a plurality of detector rings, each detector ring having a plurality of detector units, the method comprising:

• determining a line of response (LOR) connecting a first detector unit and a second detector unit of the PET scanner, wherein the LOR correlates to a plurality of coincidence events resulting from annihilation of positrons emitted by a radiation source placed at a position in a field of view (FOV) of the PET scanner, each of the plurality of coincidence events is detected by the first detector unit and the second detector unit, and each of the plurality of coincidence events has a time of flight (TOF);
• creating, based on the TOFs, a histogram having at least two peaks and representing a relationship between the TOFs and coincidence event counts relating to the TOFs;
• determining, based on the histogram, an offset value associated with the first detector unit;
• and
• calibrating, based on the offset value, the PET scanner.

A positron emission tomography (PET) system having a plurality of detector rings, and each detector ring having a plurality of detector units, the PET system comprising:

• a PET scanner;
• a coincidence event detection circuit for detecting coincidence events resulting from annihilation of positrons emitted by a hollow phantom placed at a position in a field of view (FOV) of the PET scanner;
• and
• a host computer that is configured to perform operations comprising:
• determining a line of response (LOR) connecting a first detector unit and a second detector unit of the PET scanner, wherein the LOR correlates to a plurality of coincidence events, each of the plurality of coincidence events is detected by the first detector unit and the second detector unit, and each of the plurality of coincidence events has a time of flight (TOF);
• determining, based on a relationship between the TOFs and coincidence event counts relating to the TOFs, an offset value associated with the first detector unit;
• and
• calibrating, based on the offset value, the PET scanner.