The reliability of optimization under dose-volume limits

Mark Langer, Richard Brown, Peter Kijewski, Chul Ha

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Purpose: An optimization algorithm improves the distribution of dose among discrete points in tissues, but tolerance depends on the distribution of dose across a continuous volume. This report asks whether an exact algorithm can be completed when enough points are taken to accurately model a dose-volume constraint. Methods and Materials: Trials were performed using a 3-dimensional model of conformal therapy of lung cancer Trial were repeated with different limits placed on the fraction of lung which could receive > 20 Gy. Bounds were placed on cord dose and target dose inhomogeneity. A mixed integer algorithm was used to find a feasible set of beam weights which would maximize tumor dose. Tests of feasibility and optimality are introduced to check the solution accuracy. Results: Solutions were optimal for points used to model tissues. An accuracy of 3-4% in a volume condition could be obtained with models of 450-600 points. The error improved to 2% with 800 points to model the lung. Solution times increased six-fold at this level of accuracy. Conclusion: The mixed integer method can find optimum weights which respect dose-volume conditions in usually acceptable times. If constraints are violated by an excessive amount, the optimization model should be rerun with more points.

Original languageEnglish (US)
Pages (from-to)529-538
Number of pages10
JournalInternational Journal of Radiation Oncology, Biology, Physics
Volume26
Issue number3
DOIs
Publication statusPublished - Jun 15 1993

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Keywords

  • Computer treatment planning
  • Dose-volume limits
  • Optimization

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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