Patent Number: 053430484
Section: claims

1. A contour collimator for shaping a radiation beam comprising: a holder;  two sets of radiation-impermeable lamellae disposed in said holder, each lamella in each set being individually movable toward and away from a corresponding lamella in the other set;  each lamella having a displacement element engager;  two spring means, coupled to and respectively acting on said two sets of lamellae, for generating a spring force for normally urging all lamellae in a set toward the lamellae in the other set;  two displacement elements respectively engaging said displacement element engagers of said lamellae in said sets of lamellae; and  two user-manipulable means, on which said displacement elements are respectively mounted, operable in a first manner for moving said displacement elements so as to collectively displace said sets of lamellae away from each other against said spring force and operable in a second manner for releasing said sets of lamellae so as to permit said spring force to act thereon and urge all lamella in a set toward the lamella in the other set. 2. A contour collimator as claimed in claim 1 wherein each spring means comprises a plurality of springs corresponding in number and uniquely allocated to the lamellae in a respective one of said two sets of lamellae. 3. A contour collimator as claimed in claim 2 wherein said spring means comprises a plurality of thrust rods respectively interacting with each spring and the lamella allocated thereto, each spring forcing a thrust rod against its allocated lamella. 4. A contour collimator as claimed in claim 1 further comprising means for clamping said lamellae in said sets of lamellae in a selected position upon said lamellae being released by said user-manipulable means. 5. A contour collimator as claimed in claim 4 wherein said means for clamping comprises movable lateral walls of said holder, and means for moving said movable lateral walls toward and away from said lamellae in said sets. 6. A contour collimator as claimed in claim 5 wherein said movable lateral walls are movable independently of each other. 7. A contour collimator as claimed in claim 1 wherein each lamella has a slot forming said displacement element engager, and wherein each displacement element consists of a pin extending through the respective slots of all lamellae in a set. 8. A contour collimator as claimed in claim 7 wherein each user-manipulable means includes a lever, on which said pin is mounted, and a rotatable cam interacting with said lever to move said pin to displace and to release said lamellae. 9. A contour collimator as claimed in claim 1 further comprising a form-holding plate including means for securing a form between said two sets of lamellae. 10. A contour collimator as claimed in claim 9 wherein said form-holding plate includes index means for defining alignment of said form-holding plate relative to said holder. 11. A contour collimator as claimed in claim 9 wherein said form-holding plate includes positioning means for defining alignment of a form, when secured in said means for securing, relative to said holder.