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Title: Method for selecting minimum width of leaf in multileaf adjustable collimator while inhibiting passage of particle beams of radiation through sawtooth joints between collimator leaves

A method is disclosed for selecting the minimum width of individual leaves of a multileaf adjustable collimator having sawtooth top and bottom surfaces between adjacent leaves of a first stack of leaves and sawtooth end edges which are capable of intermeshing with the corresponding sawtooth end edges of leaves in a second stack of leaves of the collimator. The minimum width of individual leaves in the collimator, each having a sawtooth configuration in the surface facing another leaf in the same stack and a sawtooth end edge, is selected to comprise the sum of the penetration depth or range of the particular type of radiation comprising the beam in the particular material used for forming the leaf; plus the total path length across all the air gaps in the area of the joint at the edges between two leaves defined between lines drawn across the peaks of adjacent sawtooth edges; plus at least one half of the length or period of a single sawtooth. To accomplish this, in accordance with the method of the invention, the penetration depth of the particular type of radiation in the particular material to be used for the collimator leaf is first measured. Then themore » distance or gap between adjoining or abutting leaves is selected, and the ratio of this distance to the height of the sawteeth is selected. Finally the number of air gaps through which the radiation will pass between sawteeth is determined by selecting the number of sawteeth to be formed in the joint. The measurement and/or selection of these parameters will permit one to determine the minimum width of the leaf which is required to prevent passage of the beam through the sawtooth joint.« less
Inventors:
 [1];  [2];  [1];  [3]
  1. (Berkeley, CA)
  2. (Hayward, CA)
  3. (Lafayette, CA)
Issue Date:
OSTI Identifier:
870012
Assignee:
Regents, University of California (Berkeley, CA) LBNL
Patent Number(s):
US 5438454
Research Org:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA
Country of Publication:
United States
Language:
English
Subject:
method; selecting; minimum; width; leaf; multileaf; adjustable; collimator; inhibiting; passage; particle; beams; radiation; sawtooth; joints; leaves; disclosed; individual; top; bottom; surfaces; adjacent; stack; edges; capable; intermeshing; corresponding; configuration; surface; facing; edge; selected; comprise; penetration; depth; range; particular; type; comprising; beam; material; forming; plus; total; path; length; air; gaps; joint; defined; lines; drawn; peaks; half; period; single; accomplish; accordance; measured; distance; gap; adjoining; abutting; ratio; height; sawteeth; finally; pass; determined; formed; measurement; selection; parameters; permit; determine; required; prevent; bottom surfaces; air gap; path length; particle beam; bottom surface; particle beams; radiation comprising; surface facing; particular type; particular material; penetration depth; minimum width; air gaps; /359/250/378/