title: Radiosurgery of multiple brain metastases with single-isocenter dynamic conformal arcs (SIDCA).
abstract: OBJECTIVE
  To propose single-isocenter dynamic conformal arcs (SIDCA), a novel technique for radiosurgery of multiple brain metastases, and to compare SIDCA with volumetric modulated arc therapy (VMAT) and multiple-isocenter dynamic conformal arcs (MIDCA) for plan quality.
  
  
  METHODS
  SIDCA, MIDCA, and VMAT plans were created on 6 patients with 3-5 metastases. Plans were evaluated using Radiation Therapy Oncology Group conformity index (RCI), Paddick conformity index (PCI), gradient index (GI), volumes that received more than 100% (V(100%)), 50% (V(50%)), 25% (V(25%)) and 10% (V(10%)) of prescription dose, total monitor units (MUs), and delivery time (DT).
  
  
  RESULTS
  SIDCA achieved conformal plans (RCI = 1.38 ± 0.12, PCI = 0.72 ± 0.06) with steep dose fall-off (GI = 3.97 ± 0.51). MIDCA plans had comparable plan quality and MUs as SIDCA, but 52% longer DT. The VMAT plans had better conformity (RCI = 1.15 ± 0.09, p < 0.01 and PCI = 0.86 ± 0.06, p < 0.01) than SIDCA, worse GI (4.34 ± 0.46, p < 0.01), higher V(25%) (p = 0.05) and V(10%) (p = 0.02), 49% less MUs and 46% shorter DT.
  
  
  CONCLUSIONS
  All three techniques achieved conformal plans with steep dose fall-off from targets. SIDCA plans had similar plan quality as MIDCA but more efficient to delivery. SIDCA plans had lower peripheral dose spread than VMAT; VMAT plans had better conformity and faster delivery time than SIDCA.
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA. Electronic address: yhuang2@hfhs.org.
authors.forename: Yimei
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Chin
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Jared R
authors.initials: JR
authors.lastname: Robbins
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Jinkoo
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Haisen
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Hanan
authors.initials: H
authors.lastname: Amro
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Indrin J
authors.initials: IJ
authors.lastname: Chetty
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: James
authors.initials: J
authors.lastname: Gordon
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, MI, USA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Ryu
mesh_terms: D001932:Brain Neoplasms / Q000532:radiotherapy / Q000556:secondary* / Q000601:surgery*; D006801:Humans; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies
keywords: Multiple brain metastases; Single-isocenter; Stereotactic radiosurgery