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Optimization of intensity-modulated radiotherapy plans based on the equivalent uniform dose.

Publication ,  Journal Article
Wu, Q; Mohan, R; Niemierko, A; Schmidt-Ullrich, R
Published in: Int J Radiat Oncol Biol Phys
January 1, 2002

PURPOSE: The equivalent uniform dose (EUD) for tumors is defined as the biologically equivalent dose that, if given uniformly, will lead to the same cell kill in the tumor volume as the actual nonuniform dose distribution. Recently, a new formulation of EUD was introduced that applies to normal tissues as well. EUD can be a useful end point in evaluating treatment plans with nonuniform dose distributions for three-dimensional conformal radiotherapy and intensity-modulated radiotherapy. In this study, we introduce an objective function based on the EUD and investigate the feasibility and usefulness of using it for intensity-modulated radiotherapy optimization. METHODS AND MATERIALS: We applied the EUD-based optimization to obtain intensity-modulated radiotherapy plans for prostate and head-and-neck cancer patients and compared them with the corresponding plans optimized with dose-volume-based criteria. RESULTS: We found that, for the same or better target coverage, EUD-based optimization is capable of improving the sparing of critical structures beyond the specified requirements. We also found that, in the absence of constraints on the maximal target dose, the target dose distributions are more inhomogeneous, with significant hot spots within the target volume. This is an obvious consequence of unrestricted maximization target cell kill and, although this may be considered beneficial for some cases, it is generally not desirable. To minimize the magnitude of hot spots, we applied dose inhomogeneity constraints to the target by treating it as a "virtual" normal structure as well. This led to much-improved target dose homogeneity, with a small, but expected, degradation in normal structure sparing. We also found that, in principle, the dose-volume objective function may be able to arrive at similar optimum dose distributions by using multiple dose-volume constraints for each anatomic structure and with considerably greater trial-and-error to adjust a large number of objective function parameters. CONCLUSION: The general inference drawn from our investigation is that the EUD-based objective function has the advantages that it needs only a small number of parameters and allows exploration of a much larger universe of solutions, making it easier for the optimization system to balance competing requirements in search of a better solution.

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Published In

Int J Radiat Oncol Biol Phys

DOI

ISSN

0360-3016

Publication Date

January 1, 2002

Volume

52

Issue

1

Start / End Page

224 / 235

Location

United States

Related Subject Headings

  • Terminology as Topic
  • Radiotherapy, Conformal
  • Radiotherapy Dosage
  • Radiobiology
  • Radiation Tolerance
  • Radiation Oncology
  • Radiation Injuries
  • Prostatic Neoplasms
  • Oncology & Carcinogenesis
  • Models, Biological
 

Citation

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Wu, Q., Mohan, R., Niemierko, A., & Schmidt-Ullrich, R. (2002). Optimization of intensity-modulated radiotherapy plans based on the equivalent uniform dose. Int J Radiat Oncol Biol Phys, 52(1), 224–235. https://doi.org/10.1016/s0360-3016(01)02585-8
Wu, Qiuwen, Radhe Mohan, Andrzej Niemierko, and Rupert Schmidt-Ullrich. “Optimization of intensity-modulated radiotherapy plans based on the equivalent uniform dose.Int J Radiat Oncol Biol Phys 52, no. 1 (January 1, 2002): 224–35. https://doi.org/10.1016/s0360-3016(01)02585-8.
Wu Q, Mohan R, Niemierko A, Schmidt-Ullrich R. Optimization of intensity-modulated radiotherapy plans based on the equivalent uniform dose. Int J Radiat Oncol Biol Phys. 2002 Jan 1;52(1):224–35.
Wu, Qiuwen, et al. “Optimization of intensity-modulated radiotherapy plans based on the equivalent uniform dose.Int J Radiat Oncol Biol Phys, vol. 52, no. 1, Jan. 2002, pp. 224–35. Pubmed, doi:10.1016/s0360-3016(01)02585-8.
Wu Q, Mohan R, Niemierko A, Schmidt-Ullrich R. Optimization of intensity-modulated radiotherapy plans based on the equivalent uniform dose. Int J Radiat Oncol Biol Phys. 2002 Jan 1;52(1):224–235.
Journal cover image

Published In

Int J Radiat Oncol Biol Phys

DOI

ISSN

0360-3016

Publication Date

January 1, 2002

Volume

52

Issue

1

Start / End Page

224 / 235

Location

United States

Related Subject Headings

  • Terminology as Topic
  • Radiotherapy, Conformal
  • Radiotherapy Dosage
  • Radiobiology
  • Radiation Tolerance
  • Radiation Oncology
  • Radiation Injuries
  • Prostatic Neoplasms
  • Oncology & Carcinogenesis
  • Models, Biological