A method for measuring a SPECT collimators hole orientation angles includes (a) providing a plurality of parallel spaced apart line radiation sources at a distance from a detector (b) positioning a first collimator between the plurality of spaced apart line radiation sources and the detector (c) obtaining a set of line images of the plurality of line radiation sources by scanning/stepping the plurality of line radiation sources across the first collimator in a first direction (d) obtaining a second set of line images of the plurality of line radiation sources by scanning/stepping the plurality of line radiation sources across the first collimator in a second direction thai is perpendicular to the first direction (c) repeating the steps (c) and (d) for a second collimator, wherein one of the two collimators is a reference collimator and the other of the two collimators is a collimator being measured.
