title: Simulated Online Adaptive Magnetic Resonance-Guided Stereotactic Body Radiation Therapy for the Treatment of Oligometastatic Disease of the Abdomen and Central Thorax: Characterization of Potential Advantages.
abstract: To characterize potential advantages of online-adaptive magnetic resonance (MR)-guided stereotactic body radiation therapy (SBRT) to treat oligometastatic disease of the non-liver abdomen and central thorax.
  
  
  
  Ten patients treated with RT for unresectable primary or oligometastatic disease of the non-liver abdomen (n=5) or central thorax (n=5) underwent imaging throughout treatment on a clinical MR image guided RT system. The SBRT plans were created on the basis of tumor/organ at risk (OAR) anatomy at initial computed tomography simulation (PI), and simulated adaptive plans were created on the basis of observed MR image set tumor/OAR "anatomy of the day" (PA). Each PAwas planned under workflow constraints to simulate online-adaptive RT. Prescribed dose was 50 Gy/5 fractions, with goal coverage of 95% planning target volume (PTV) by 95% of the prescription, subject to hard OAR constraints. The PIwas applied to each MR dataset and compared with PAto evaluate changes in dose delivered to tumor/OARs, with dose escalation when possible.
  
  
  
  Hard OAR constraints were met for all PIsbased on anatomy from initial computed tomography simulation, and all PAsbased on anatomy from each daily MR image set. Application of the PIto anatomy of the day caused OAR constraint violation in 19 of 30 cases. Adaptive planning increased PTV coverage in 21 of 30 cases, including 14 cases in which hard OAR constraints were violated by the nonadaptive plan. For 9 PAcases, decreased PTV coverage was required to meet hard OAR constraints that would have been violated in a nonadaptive setting.
  
  
  
  Online-adaptive MRI-guided SBRT may allow PTV dose escalation and/or simultaneous OAR sparing compared with nonadaptive SBRT. A prospective clinical trial is underway at our institution to evaluate clinical outcomes of this technique.
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Lauren
authors.initials: L
authors.lastname: Henke
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Rojano
authors.initials: R
authors.lastname: Kashani
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Deshan
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Olga
authors.initials: O
authors.lastname: Green
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Olsen
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Vivian
authors.initials: V
authors.lastname: Rodriguez
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: H Omar
authors.initials: HO
authors.lastname: Wooten
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: H Harold
authors.initials: HH
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Yanle
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Bradley
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Clifford
authors.initials: C
authors.lastname: Robinson
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Parag
authors.initials: P
authors.lastname: Parikh
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Jeff
authors.initials: J
authors.lastname: Michalski
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Sasa
authors.initials: S
authors.lastname: Mutic
authors.affiliation: Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. Electronic address: Jeffrey.R.Olsen@ucdenver.edu.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Olsen
mesh_terms: D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary; D000368:Aged; D000369:Aged, 80 and over; D004386:Duodenum / Q000000981:diagnostic imaging; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008875:Middle Aged; D058958:Organs at Risk / Q000000981:diagnostic imaging; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013270:Stomach / Q000000981:diagnostic imaging; D013899:Thoracic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary; D014057:Tomography, X-Ray Computed / Q000379:methods