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leaf-sequencing for IMRT - Coggle Diagram

- - - - extraction (determined by exhaustive search)
        
        rod pushing (similar to sweeping)
        
        modifications (to meet MLC constraints)
      - unconstrained or constrained (concerning collision, tongue-and-groove effect)
    - - concerning mainly NS
      - delivery sequence decided by the max intensity of the residual matrix (nth powers of 2)
        
        "reducing level" technique
        
        "sliding window" technique
        
        "sliding window": delivery sequence is set based on the 2 left-most nonzero intensity columns (delivery intensities goes in a cycle), minimizes leaf movements
        
        "reducing level": delivery sequence is set based on the maximum intensity level of the intensity matrix (delivery intensities goes from high to low)
      - constrained or unconstrained
    - - optimal for the TNMU and approximately optimal for the NS
      - Kamal, R., Singh, G., Thaper, D., Oinam, A. S., Handa, B., Kumar, V., & Kapoor, R. (2020). Efficiency of a novel non-monotonic segmented leaf sequence delivery of Varian MLC for non-split IMRT fields. Reports of Practical Oncology and Radiotherapy, 25(5), 801-807.
        
        improve the efficiency by adding minimum segment width constraint
      - complexity: O(m^2 n^3)
      - unconstrained
  - - - smallest possible TNMU but a large NS
      - interpolation
        
        rebinning (as a function of fluence levels)
        
        leaf position setting
    - - Kamath, S., Sahni, S., Li, J., Palta, J., & Ranka, S. (2003). Leaf sequencing algorithms for segmented multileaf collimation. Physics in Medicine & Biology, 48(3), 307.
        
        proved that leaf sequencing based on unidirectional movement of the MLC leaves is as MU efficient as bidirectional movement of the MLC leaves
        
        SINGLEPAIR algorithm
        
        also adding modifications concerning min inter- and intra-leaf separation constraint