Patent Number: 
Section: claims

1. A collimator system comprising: a plurality of movable plates stacked one above another, said plates being constructed of a material substantially impervious to passage therethrough of radiation in a predetermined range of wavelengths; and  at least one collimator aperture formed in each of said plates, wherein each of said plates is independently rotatable about a common axis. 2. The collimator system according to  claim 1  wherein said plates are arranged relative to each other such that said collimator apertures formed in neighboring plates are alignable with each other to form a collimation path adapted for a radiation beam to pass therethrough. claim 1 3. The collimator system according to  claim 1  wherein one of said collimator apertures on one of said plates has a different sized opening than a collimator aperture on another of said plates. claim 1 4. The collimator system according to  claim 1  wherein at least one of said plates is formed with a plurality of differently sized collimator apertures. claim 1 5. The collimator system according to  claim 1  wherein at least one of said plates is formed with a plurality of generally equally sized collimator apertures. claim 1 6. The collimator system according to  claim 1  wherein a gap between neighboring plates of said plurality of movable plates is sufficiently small such that a radiation beam of a predetermined wavelength is substantially prevented from passing through said gap. claim 1 7. The collimator system according to  claim 1  further comprising a controller connected to said plates which selectively revolves said plates. claim 1 8. The collimator system according to  claim 7  wherein said controller comprises a servomotor linked to said plates which selectively revolves said plates. claim 7 9. The collimator system according to  claim 1  wherein a subset of said plates are mechanically linked together and are mounted on bearings about a common axle, such that said subset of plates revolves together independently of the other plates. claim 1 10. The collimator system according to  claim 1  further comprising a stop mechanism which selectively arrests movement of said plates. claim 1 11. A collimator system comprising: a plurality of movable plates stacked one above another, said plates being constructed of a material substantially impervious to passage therethrough of radiation in a predetermined range of wavelengths; and  at least one collimator aperture formed in each of said plates, wherein at least one of said plates has a thickness different from another of said plates.