A tilting collimator (4), in particular usable in the single photon emission computed tomography imaging technique, comprises: a plurality of side-by-side tubular structures (5), apt to form a matrix of tubular structures (5) on a two-dimensional space, each tubular structure (5) comprising at least a through hole; each tubular structure (5) being in contact with the tubular structures (5) adjacent thereto so as to be able to tilt only in presence of an equal tilting in the adjacent tubular structures (5); and retaining means, acting on the outer edges of said matrix, apt to move horizontally to determine the simultaneous tilting of all tubular structures (5) of the matrix, allowing a three-dimensional scanning of a gamma source by tilting progressively the single tubular structures (5) with great precision and in an extremely quick way.