A tilting collimator, usable in the single photon emission computed tomography imaging technique, comprising: • a plurality of side-by-side tubular structures, apt to form a matrix of tubular structures on a two-dimensional space; each tubular structure being in contact with the tubular structures adjacent thereto so as to be able to tilt only in presence of an equal tilting in the adjacent tubular structures, each tubular structure comprising at least a through hole; and the tilting collimator further comprising a box-like structure with a substantially squared shape;and • retaining means, acting on the outer edges of said matrix, apt to move horizontally to determine the simultaneous tilting of all tubular structures of the matrix and adapted to act at distal ends of the tubular structures by pushing in a horizontal pushing direction on a matrix side and by accompanying the forward motion of the distal ends at the opposite side, said retaining means including a pair of slats adhering laterally to the tubular structures, so as to contain them, and, at each end of a tubular structure, respective fastening members, wherein each fastening member further comprises, at the face directed towards the inner surface of the box-like structure, a wheel idly arranged on a pin projecting from the base of the fastening member, the wheel diameter being so that each wheel is in contact with the wheels of the adjacent tubular structures; and wherein each pin further comprises a head received in a groove formed inside the vertical wall of the box-like structure; • a guide provided at the two sides of each tubular structure, the guide having concavity cooperating with a corresponding rib formed at opposite sides of the adjacent tubular structure. • a plurality of side-by-side tubular structures, apt to form a matrix of tubular structures on a two-dimensional space; each tubular structure being in contact with the tubular structures adjacent thereto so as to be able to tilt only in presence of an equal tilting in the adjacent tubular structures, each tubular structure comprising at least a through hole; and the tilting collimator further comprising a box-like structure with a substantially squared shape;and • retaining means, acting on the outer edges of said matrix, apt to move horizontally to determine the simultaneous tilting of all tubular structures of the matrix and adapted to act at distal ends of the tubular structures by pushing in a horizontal pushing direction on a matrix side and by accompanying the forward motion of the distal ends at the opposite side, said retaining means including a pair of slats adhering laterally to the tubular structures, so as to contain them, and, at each end of a tubular structure, respective fastening members, wherein each fastening member further comprises, at the face directed towards the inner surface of the box-like structure, a wheel idly arranged on a pin projecting from the base of the fastening member, the wheel diameter being so that each wheel is in contact with the wheels of the adjacent tubular structures; and wherein each pin further comprises a head received in a groove formed inside the vertical wall of the box-like structure; • a guide provided at the two sides of each tubular structure, the guide having concavity cooperating with a corresponding rib formed at opposite sides of the adjacent tubular structure.