Patent ID: 7732773

Claim:
A method, comprising: positioning a radioactive tracer inside a sample, wherein said tracer interacts with said sample to emit a first annihilation gamma-ray and a second annihilation gamma-ray, wherein said first annihilation gamma-ray and said second annihilation gamma-ray are emitted at about 180 degrees from each other; intercepting said first annihilation gamma-ray with a first position sensitive detector (PSD), wherein said first annihilation gamma-ray produces a first plurality of photon reactions comprising a first photon reaction A in said first PSD and at least one subsequent photon reaction A′ in said first PSD; intercepting said second annihilation gamma-ray with a second PSD, wherein said second annihilation gamma-ray produces a second plurality of photon reactions comprising a first photon reaction B in said second PSD and at least one subsequent photon reaction B′ in said second PSD; determining, with a Bayesian probability theory based gamma-ray tracking algorithm, which photon of said first plurality of photon reactions has the highest probability of being said first photon reaction A; determining, with said gamma-ray tracking algorithm, which photon of said second plurality of photon reactions has the highest probability of being a first photon reaction B; and producing a line of response between said first photon reaction A and said first photon reaction B.