Patent ID: 7238946

Claim:
A gamma camera, comprising: a plurality of bar detector modules, each comprising a plurality of elongated scintillation crystal bars, each bar having two end surfaces, said plurality of bars being arranged in a two-dimensional array with respect to said end surfaces, and at least two photosensors, each optically coupled to a respective end of said module, for detecting a scintillation interaction of a gamma photon with one of said bars; and a position calculator for determining the spatial location of a detected scintillation interaction in the elongated dimension of a scintillation crystal bar, according to the formula: z ^ = arg ∀ z ⁢ ⁢ min z = z ^ ⁢ ( ( R - μ R ⁡ ( z ) ) 2 σ R 2 ⁡ ( z ) ) where z is the elongated dimension of said bar, R = E 1 - E 2 E 1 + E 2 , E 1 =the total energy detected at a first end of said bar, E 2 =the total energy detected at a second end of said bar, μ R =the mean of ratio R at a given location z, and σ R =the variance of the ratio Rat a given location z.