title: Whole brain radiotherapy with hippocampal avoidance and simultaneous integrated boost for brain metastases: a dosimetric volumetric-modulated arc therapy study.
abstract: OBJECTIVE
  To develop a feasible volumetric modulated arc therapy (VMAT) treatment in whole brain radiotherapy (WBRT) with a simultaneous integrated boost (SIB) and hippocampal (HP) sparing in 1-5 brain metastases (BMs).
  
  
  METHODS
  Ten patients with 20 BMs received a WBRT prescription of 20 Gy, SIB dose on BMs of 40 Gy/5 fractions. PTVWBRT was generated from brain minus BMs-PTVs (PTVSIB) and planning organ at risk volume to HP. All plans were evaluated in: homogeneity index (HI), target coverage (TC), maximum dose to prescription dose ratio (MDPD), prescription isodose to target volume ratio (PITV) and paddick conformity index (CI). We also evaluate D100%, mean and maximum doses to HP. Planning objectives were for PTVWBRT, D2% = 25 Gy with acceptable deviation of 26.7 Gy and D98% ≥ 16.7 Gy; for PTVSIB D95% ≥ 38 Gy; for HP, D100% = 6 Gy with acceptable deviation of 6.7 Gy, Dmax = 10.7 Gy with acceptable deviation of 11.3 Gy, a mean dose of 8 Gy.
  
  
  RESULTS
  Mean number of BMs was 2 (range 1-5). Mean values for BMs were volume of PTVSIB = 5.1 ± 4.9 cc, dose to 95% of PTVSIB 39.3 ± 0.9 Gy, HI 0.083 ± 0.03, TC 0.96 ± 0.24, CI 0.78 ± 0.17. Mean MDPD was 1.06 ± 0.02 and PITV 0.96 ± 0.24. For WBRT, mean target volume was (13.46 ± 2)*10(2) cc, mean dose to 90% of PTVWBRT 19.8 ± 0.2 Gy, mean HI 0.42 ± 0.12 and TC 0.78 ± 0.11. Mean and maximum HP doses were 7.7 ± 0.3 Gy and 10.5 ± 0.5 Gy. Mean dose to 100% of HP volume (D100%) was 6.7 ± 0.3 Gy.
  
  
  CONCLUSIONS
  WBRT plus SIB with HP avoidance with VMAT was feasible. All dosimetric parameters were satisfied for PTVWBRT and PTVSIB.
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Niccolò
authors.initials: N
authors.lastname: Giaj Levra
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Gianluisa
authors.initials: G
authors.lastname: Sicignano
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Alba
authors.initials: A
authors.lastname: Fiorentino
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Fersino
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ricchetti
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.|Radiation Oncology School, University of Palermo, Palermo, Italy.
authors.forename: Rosario
authors.initials: R
authors.lastname: Mazzola
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Naccarato
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy.
authors.forename: Ruggero
authors.initials: R
authors.lastname: Ruggieri
authors.affiliation: Radiation Oncology Department, Sacro Cuore Hospital, Via Don A.Sempreboni 5, 37024, Negrar, Verona, Italy. dott.filippoalongi@gmail.com.
authors.forename: Filippo
authors.initials: F
authors.lastname: Alongi
mesh_terms: D001932:Brain Neoplasms / Q000532:radiotherapy*; D016371:Cranial Irradiation / Q000379:methods*; D019583:Dose Fractionation, Radiation; D005260:Female; D006624:Hippocampus / Q000528:radiation effects; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D056888:Patient Positioning; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*
keywords: Hippocampal avoidance; Hypofractionated radiotherapy; Simultaneous integrated boost; Whole brain radiotherapy