The invention relates to a multi-leaf collimator (1) with leaf drives (2), with two sets (4, 4) of displaceable leaves (3, 3, 3",...) arranged side by side of each other and facing each other in order to impress a high-energy beam (5) with the shape of an irregularly formed treatment object (6) by enabling each of the leaves (2) to assume a position oriented along the shape of the treatment object (6) by means of a leaf drive (2), with the leaf drives (2) being designed in such a way that the leaves (3, 3, 3",...) are each equipped with a gear rod-like drive engagement (8, 8, 8",....) in the direction of the displacement (7). The invention facilitates a design of leaf drives as compact and lightweight as possible and an advantageous arrangement in an irradiation head due to the fact that a leaf-side pivotable gear segment (9, 9, 9",... ) located, together with a motor-side gear segment (10, 10, 10",...), on a segment disk (11, 11, 11",...) engages with the gear rod-like drive engagement (8, 8, 8",....), with a pinion (13) drivable by a motor (12) engaging with the motor-side gear segment (10, 10, 10,...) that the segment discs (11, 11, 11",...) are arranged side by side for each set (4, 4) of leaves (3, 3, 3",...) as a package (15) on one axis (14) and that the motor-side gear segments (10, 10, 10",...) of two segment disks (11, 11, 11",...) located next to each other are staggered in such a way that they will not abut each other that the segment disks (11, 11, 11",...) are positioned on a radiation source-facing side (46) of the leaves (3, 3, 3",...) and that the segment disks (11, 11, 11",...) have a radius (R) that is comparable to a predefined range of displacement (D) of the leaves (3, 3, 3",...).Linvention concerne un diaphragme de profondeur (1) avec des entraînements de lamelle (2), avec deux ensembles (4, 4) de lamelles pouvant être déplacées (3, 3, 3",...) agencés mutuellement côte à côte et se faisant face mutuellement afin dimprimer un faisceau à haute é
