title: A DVH-guided IMRT optimization algorithm for automatic treatment planning and adaptive radiotherapy replanning.
abstract: OBJECTIVE
  To develop a novel algorithm that incorporates prior treatment knowledge into intensity modulated radiation therapy optimization to facilitate automatic treatment planning and adaptive radiotherapy (ART) replanning.
  
  
  METHODS
  The algorithm automatically creates a treatment plan guided by the DVH curves of a reference plan that contains information on the clinician-approved dose-volume trade-offs among different targets/organs and among different portions of a DVH curve for an organ. In ART, the reference plan is the initial plan for the same patient, while for automatic treatment planning the reference plan is selected from a library of clinically approved and delivered plans of previously treated patients with similar medical conditions and geometry. The proposed algorithm employs a voxel-based optimization model and navigates the large voxel-based Pareto surface. The voxel weights are iteratively adjusted to approach a plan that is similar to the reference plan in terms of the DVHs. If the reference plan is feasible but not Pareto optimal, the algorithm generates a Pareto optimal plan with the DVHs better than the reference ones. If the reference plan is too restricting for the new geometry, the algorithm generates a Pareto plan with DVHs close to the reference ones. In both cases, the new plans have similar DVH trade-offs as the reference plans.
  
  
  RESULTS
  The algorithm was tested using three patient cases and found to be able to automatically adjust the voxel-weighting factors in order to generate a Pareto plan with similar DVH trade-offs as the reference plan. The algorithm has also been implemented on a GPU for high efficiency.
  
  
  CONCLUSIONS
  A novel prior-knowledge-based optimization algorithm has been developed that automatically adjust the voxel weights and generate a clinical optimal plan at high efficiency. It is found that the new algorithm can significantly improve the plan quality and planning efficiency in ART replanning and automatic treatment planning.
authors.affiliation: Department of Radiation Medicine and Applied Sciences and Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California 92037-0843.
authors.forename: Masoud
authors.initials: M
authors.lastname: Zarepisheh
authors.affiliation: Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, Michigan 48109-2117.
authors.forename: Troy
authors.initials: T
authors.lastname: Long
authors.affiliation: Department of Radiation Medicine and Applied Sciences and Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California 92037-0843.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Radiation Medicine and Applied Sciences and Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California 92037-0843 and Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8542.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, Michigan 48109-2117.
authors.forename: H Edwin
authors.initials: HE
authors.lastname: Romeijn
authors.affiliation: Department of Radiation Medicine and Applied Sciences and Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California 92037-0843 and Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8542.
authors.forename: Xun
authors.initials: X
authors.lastname: Jia
authors.affiliation: Department of Radiation Medicine and Applied Sciences and Center for Advanced Radiotherapy Technologies, University of California San Diego, La Jolla, California 92037-0843 and Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8542.
authors.forename: Steve B
authors.initials: SB
authors.lastname: Jiang
mesh_terms: D000465:Algorithms; D001330:Electronic Data Processing; D006258:Head and Neck Neoplasms / Q000188:drug therapy; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D019233:Retreatment / Q000379:methods