Patent Number: 
Section: claims

1. A contour collimator for radiotherapy, comprisinga plurality of plate-shaped diaphragm elements provided in a guiding block and movably arranged with respect to one another to form a contour diaphragm for a radiation beam emitted by a radiation source towards the collimator, andat least one drive for moving the diaphragm elements, whereineach diaphragm element is associated with its own drive of the at least one drive, the drives of a group of diaphragm elements are arranged substantially adjacent to one another, and each drive is a linear motor, whereineach linear motor comprises a linearly movable rod directly fixed to the associated diaphragm element,wherein the linear motors of a group of diaphragm elements are arranged in horizontal and vertical rows, a vertical row of linear motors is associated with a sub-group of diaphragm elements adjacent to each other in a horizontal direction,wherein each diaphragm element comprises a portion extended towards an associated linear motor, the extended portion comprises an angled portion located at an end facing the linear motor, wherein an associated rod is fixed to the angled portion,wherein extended portions of a sub-group of the diaphragm elements are connected to the angled portions at positions shifted in a horizontal direction, andwherein extended portions of a sub-group of the diaphragm elements are offset from a longitudinal axis of the associated rods. 2. The contour collimator according to claim 1, wherein each linear motor and the associated diaphragm element are arranged substantially within a common plane. 3. The contour collimator according to claim 1, wherein the linear motors of a group of diaphragm elements are arranged parallel to each other. 4. The contour collimator according to claim 1, wherein each linear motor comprises a housing, wherein the rod is extendable through the housing. 5. The contour collimator according to claim 1, wherein each linear motor comprises coils, wherein the rod comprises magnets, wherein the rod is arranged so as to be linearly movable between the coils. 6. The contour collimator according to claim 1, wherein the rod is welded or screwed to the associated diaphragm element. 7. The contour collimator according to claim 1, wherein the angled portions of a sub-group of diaphragm elements are arranged at the same position in a horizontal direction. 8. The contour collimator according to claim 1, wherein the rod protrudes from the linear motor in a direction facing away from the diaphragm element in a retracted position of the rod.