Patent ID: 7283611

Claim:
A method comprising the following steps: (a) recursively partitioning an intensity modulated beam into plateaus; (b) partitioning the plateaus into segments; and (p) administering radiation therapy using the segments; and wherein the method further comprises: (c) constructing a directed graph based on the plateaus; (d) determining a maximum flow in the directed graph; and (e) extracting the segments from the directed graph based on the maximum flow determined in step (d) to thereby partition the plateaus; and wherein step (c) comprises the following steps: (f) constructing a directed graph based on intensity modulated beam grids of the plateaus of an intensity modulated beam, wherein vertices of the directed graph include all intersection points of the intensity modulated beam grids of the plateaus that are either part of a peak or an interior of a polygon corresponding to the intensity modulated beam, and wherein the edges of the directed graph include those edges of the plateaus whose end points are graph vertices in the directed graph; (g) for all graph vertices corresponding to the same peak direction, adding either a source vertex or sink vertex to the directed graph; (h) adding edges to the directed graph from the source vertex or sink vertex to respective peak vertices; and (i) assigning a unit flow capacity to each graph vertex and edge of the directed graph.