A three-dimensional algorithm for optimizing beam weights and wedge filters

Lei Xing, R. J. Hamilton, C. Pelizzari, G. T.Y. Chen

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


An essential step towards optimizing and automating radiation therapy treatment planning is to develop an effective algorithm to find the optimal beam weights and wedge filters for a given set of beam directions and modalities. This problem is solved by introducing a variable transformation based on the universal and omni wedge principles. Instead of directly optimizing an objective function with respect to wedge angles and orientations, each field is first decomposed into a superposition of an open field and two orthogonal wedged fields. This transforms the problem of finding J beam weights, wedge angles, and orientations to that of optimizing a system with 3J beam weights (J open beams and 2J nominal wedged beams), where J is the total number of incident beam directions. An iterative algorithm based on a method originally developed for image reconstruction is used to find the 3J beam weights. The technique is applied to a few clinical cases. Treatment plans are improved compared to those obtained through the conventional manual trial and error planning process. In addition, planning time and effort are greatly reduced.

Original languageEnglish (US)
Pages (from-to)1858-1865
Number of pages8
JournalMedical physics
Issue number10
StatePublished - Oct 1998


  • Conformal radiotherapy
  • Optimization
  • Treatment planning
  • Wedge

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging


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