title: Using overlap volume histogram and IMRT plan data to guide and automate VMAT planning: a head-and-neck case study.
abstract: OBJECTIVE
  To investigate whether an overlap volume histogram (OVH)-driven planning application using an intensity-modulated radiation therapy (IMRT) database can guide and automate volumetric-modulated arc therapy (VMAT) planning for head-and-neck cancer.
  
  
  METHODS
  Based on comparable head-and-neck dosimetric results between planner-generated VMAT and IMRT plans, an inhouse developed, OVH-driven automated planning application containing a database of prior clinical head-and-neck IMRT plans is built into Pinnacle(3) SmartArc for VMAT planning. Double-arc VMAT plans of four oropharynx, four nasopharynx, and four larynx patients are generated and compared with corresponding clinical IMRT plans.
  
  
  RESULTS
  Each VMAT plan is automatically generated in two optimization rounds, while the average number of optimization rounds in generating a clinical IMRT plan is 43. In VMAT plans, statistical superiority (p < 0.01) in sparing of the cord+4 mm, brainstem, brachial plexus, larynx, and inner ear is observed with a slight degradation in low-dose-level planning target volume (PTV) coverage. On average, D(0.1 cc) to the cord+4 mm, brainstem and brachial plexus is reduced by 3.7, 4.9, and 1.6 Gy, respectively; V(50 Gy) to the larynx is reduced by 5.3%; mean dose to the inner ear is reduced by 4.4 Gy; V(95) of low-dose-level PTV coverage is reduced by 0.3% with p = 0.25.
  
  
  CONCLUSIONS
  IMRT-data-driven VMAT planning offers a potential method for generating VMAT plans that are comparable to IMRT plans in terms of dosimetric quality.
authors: Department of Radiation Medicine, Georgetown University Hospital, Washington, DC 20007, USA. binbin.wu@gunet.georgetown.edu
authors: Binbin
authors: B
authors: Wu
authors: Dalong
authors: D
authors: Pang
authors: Patricio
authors: P
authors: Simari
authors: Russell
authors: R
authors: Taylor
authors: Giuseppe
authors: G
authors: Sanguineti
authors: Todd
authors: T
authors: McNutt
mesh_terms: D001331:Automation; D006258:Head and Neck Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D058958:Organs at Risk / Q000528:radiation effects; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D047368:Tumor Burden / Q000528:radiation effects*