Dual energy window scatter corrections for positron emission tomography

A simulation of PET (positron emission tomography) was used to investigate dual energy window scatter correction for PET devices. Two types of off-peak energy windows were examined. Method one only accepts coincidences where the detected energies of both photons are in the off-peak energy window; method two accepts coincidences where the detected energy of one photon is in the off-peak window and the detected energy of the other photon is in either the off-peak or on-peak window. Profiles of the coincidence accepted by these methods were compared to profiles of the scatter coincidences detected in the on-peak window. Neither method produces a good approximation to the shape of the scatter coincidence profile. Method one has little to recommend it over a constant background subtraction. Method two yields profiles that looked even less useful, dipping down where the scatter coincidence profile rises.<>