title: Dose-painting IMRT optimization using biological parameters.
abstract: OBJECTIVE
  Our work on dose-painting based on the possible risk characteristics for local recurrence in tumor subvolumes and the optimization of treatment plans using biological objective functions that are region-specific are reviewed.
  
  
  METHODS
  A series of intensity modulated dose-painting techniques are compared to their corresponding intensity modulated plans in which the entire PTV is treated to a single dose level, delivering the same equivalent uniform dose (EUD) to the entire PTV. Iso-TCP and iso-NTCP maps are introduced as a tool to aid the planner in the evaluation of the resulting non-uniform dose distributions. Iso-TCP and iso-NTCP maps are akin to iso-dose maps in 3D conformal radiotherapy. The impact of the currently limited diagnostic accuracy of functional imaging on a series of dose-painting techniques is also discussed.
  
  
  RESULTS
  Utilizing biological parameters (risk-adaptive optimization) in the generation of dose-painting plans results in an increase in the therapeutic ratio as compared to conventional dose-painting plans in which optimization techniques based on physical dose are employed.
  
  
  CONCLUSIONS
  Dose-painting employing biological parameters appears to be a promising approach for individualized patient- and disease-specific radiotherapy.
authors.affiliation: Department of Radiation Oncology, University of Iowa, Iowa City, USA.
authors.forename: Yusung
authors.initials: Y
authors.lastname: Kim
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Tomé
mesh_terms: D006801:Humans; D016015:Logistic Models; D009369:Neoplasms / Q000532:radiotherapy; D016012:Poisson Distribution; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*