Patent Number: 
Section: claims

1. A multileaf collimator, comprising:a plurality of beam-blocking leaves of a first type, each of the plurality of beam-blocking leaves of the first type having a trapezoidal geometry viewed in a longitudinal moving direction with a first lateral side, a second lateral side, a wider end, and a narrower end, the wider end being proximal to a source;a plurality of beam-blocking leaves of a second type, each of the plurality of beam-blocking leaves of the second type having a trapezoidal geometry viewed in the longitudinal moving direction with a first lateral side, a second lateral side, a wider end, and a narrower end, the wider end being distal to the source; andthe plurality of beam-blocking leaves of the first type being alternatingly arranged with the plurality of beam-blocking leaves of the second type side by side. 2. The multileaf collimator of claim 1, whereinfirst lateral sides of the plurality of beam-blocking leaves of the first type align to converge to a first point offset from the source, andsecond lateral sides of the plurality of beam-blocking leaves of the first type align to converge to a second point offset from the source and opposite to the first point. 3. The multileaf collimator of claim 2, whereinwherein a first lateral side of a beam-blocking leaf of the second type is adjacent to a second lateral side of a beam-blocking leaf of the first type, and a second lateral side of a beam-blocking leaf of the second type is adjacent to a first lateral side of a beam-blocking leaf of the first type, andfirst lateral sides of the plurality of beam-blocking leaves of the second type align to converge to the second point, and second lateral sides of the plurality of beam-blocking leaves of the second type align to converge to the first point. 4. The multileaf collimator of claim 3, wherein the first point offsets from the source at a distance substantially equal to a distance that the second point offsets from the source. 5. The multileaf collimator of claim 1, wherein a first lateral side and a second lateral side of each of the plurality of beam-blocking leaves of the first type, and a first lateral side and a second lateral side of each of the plurality of beam-blocking leaves of the second type are substantially flat. 6. The multileaf collimator of claim 5, wherein the first point offsets from the source at a distance substantially equal to a distance that the second point offsets from the source. 7. The multileaf collimator of claim 1, wherein a first lateral side and a second lateral side of each of the plurality of beam-blocking leaves of the first type, and a first lateral side and a second lateral side of each of the plurality of beam-blocking leaves of the second type are substantially flat. 8. A multi-level multileaf collimator (MLC), comprising:a first MLC in a first level distal to a source; anda second MLC in a second level proximal to the source,wherein the second MLC comprises:a plurality of beam-blocking leaves of a first type, each of the plurality of beam-blocking leaves of the first type having a trapezoidal geometry viewed in a longitudinal moving direction with a first lateral side, a second lateral side, a wider end and a narrower end, the wider end being proximal to the source;a plurality of beam-blocking leaves of a second type, each of the plurality of beam-blocking leaves of the second type having a trapezoidal geometry viewed in the longitudinal moving direction with a first lateral side, a second lateral side, a wider end, and a narrower end, the wider end being distal to the source; andthe plurality of beam-blocking leaves of the first type being alternatingly arranged with the plurality of beam-blocking leaves of the second type side by side. 9. The multi-level multileaf collimator of claim 8, whereinfirst lateral sides of the plurality of beam-blocking leaves of the first type align to converge to a first point offset from the source, andsecond lateral sides of the plurality of beam-blocking leaves of the first type align to converge to a second point offset from the source opposite to the first point. 10. The multi-level multileaf collimator of claim 9, whereinwherein a first lateral side of a beam-blocking leaf of the second type is adjacent to a second lateral side of a beam-blocking leaf of the first type, and a second lateral side of a beam-blocking leaf of the second type is adjacent to a first lateral side of a beam-blocking leaf of the first type, andfirst lateral sides of the plurality of beam-blocking leaves of the second type align to converge to the second point, and second lateral sides of the plurality of beam-blocking leaves of the second type align to converge to the first point. 11. The multi-level multileaf collimator of claim 10, wherein the first point offsets from the source at a distance substantially equal to a distance that the second point offsets from the source. 12. The multi-level multileaf collimator of claim 8, wherein a first lateral side and a second lateral side of each of the plurality of beam-blocking leaves of the first type, and a first lateral side and a second lateral side of each of the plurality of beam-blocking leaves of the second type are substantially flat. 13. The multi-level multileaf collimator of claim 8, wherein the first MLC comprises a plurality of beam-blocking leaves, each being longitudinally movable in a direction substantially parallel with the longitudinal moving direction of the plurality of beam-blocking leaves of the first type and the plurality of beam-blocking leaves of the second type of the second MLC. 14. The multi-level multileaf collimator of claim 13, wherein each of the plurality of beam-blocking leaves of the first type and the plurality of beam-blocking leaves of the second type of the second MLC laterally offsets a beam-blocking leaf of the first MLC. 15. An apparatus, comprising:a source of radiation, anda multileaf collimator comprising:a plurality of beam-blocking leaves of a first type, each of the plurality of beam-blocking leaves of the first type having a trapezoidal geometry viewed in a longitudinal moving direction with a first lateral side, a second lateral side, a wider end, and a narrower end, the wider end being proximal the source of radiation;a plurality of beam-blocking leaves of a second type, each of the plurality of beam-blocking leaves of the second type having a trapezoidal geometry viewed in the longitudinal moving direction with a first lateral side, a second lateral side, a wider end, and a narrower end, the wider end being distal to the source of radiation; andthe plurality of beam-blocking leaves of the first type being alternatingly arranged with the plurality of beam-blocking leaves of the second type side by side. 16. The apparatus of claim 15, wherein the source of radiation comprises a source of x-rays, a source of gamma rays, a source of protons, or a source of heavy ions. 17. The apparatus of claim 15, wherein the multileaf collimator comprises a first multileaf collimator in a first level distal to the source of radiation and a second multileaf collimator in a second level proximal to the source of radiation, wherein the plurality of beam-blocking leaves of the first type and the plurality of beam-blocking leaves of the second type are arranged in the second multileaf collimator. 18. The apparatus of claim 17, wherein the first multileaf collimator comprises a plurality of beam-blocking leaves, and each of the plurality of beam-blocking leaves of the first type and the plurality of beam-blocking leaves of the second type of the second multileaf collimator laterally offsets one of the plurality of beam-blocking leaves of the first multileaf collimator. 19. The apparatus of claim 15, whereinfirst lateral sides of the plurality of beam-blocking leaves of the first type align to converge to a first point offset from the source, andsecond lateral sides of the plurality of beam-blocking leaves of the first type align to converge to a second point offset from the source opposite to the first point. 20. The apparatus of claim 19, whereina first lateral side of a beam-blocking leaf of the second type is adjacent to a second lateral side of a beam-blocking leaf of the first type, and a second lateral side of a beam-blocking leaf of the second type is adjacent to a first lateral side of a beam-blocking leaf of the first type, andfirst lateral sides of the plurality of beam-blocking leaves of the second type align to converge to the second point, and second lateral sides of the plurality of beam-blocking leaves of the second type align to converge to the first point.