title: Dosimetric Comparison and Evaluation of 4 Stereotactic Body Radiotherapy Techniques for the Treatment of Prostate Cancer.
abstract: The aim of this study was to compare dosimetric characteristics, monitor unit, and delivery efficiency of 4 different stereotactic body radiotherapy techniques for the treatment of prostate cancer.
  
  
  
  This study included 8 patients with localized prostate cancer. Dosimetric assets of 4 delivery techniques for stereotactic body radiotherapy were evaluated: robotic CyberKnife, noncoplanar intensity-modulated radiotherapy, and 2 intensity-modulated arc therapy techniques (RapidArc and Elekta volumetric-modulated arc therapy). All the plans had equal treatment margins and a prescription dose of 35 Gy in 5 fractions.
  
  
  
  Statistically significant differences were observed in homogeneity index and mean doses of bladder wall and penile bulb, all of which were highest with CyberKnife. No significant differences were observed in the mean doses of rectum, with values of 15.2 ± 2.6, 13.3 ± 2.6, 13.1 ± 2.8, and 13.8 ± 1.6 Gy with CyberKnife, RapidArc, volumetric-modulated arc therapy, and noncoplanar intensity-modulated radiotherapy, respectively. The highest dose conformity was realized with RapidArc. The dose coverage of the planning target volume was lowest with noncoplanar intensity-modulated radiotherapy. Treatment times and number of monitor units were largest with CyberKnife (on average 34.0 ± 5.0 minutes and 8704 ± 1449 monitor units) and least with intensity-modulated arc therapy techniques (on average 5.1 ± 1.1 minutes and 2270 ± 497 monitor units).
  
  
  
  Compared to CyberKnife, the RapidArc, volumetric-modulated arc therapy, and noncoplanar intensity-modulated radiotherapy produced treatment plans with similar dosimetric quality, with RapidArc achieving the highest dose conformity. Overall, the dosimetric differences between the studied techniques were marginal, and thus, the choice of the technique should rather focus on the delivery accuracies and dose delivery times.
authors.affiliation: 1 Radiotherapy Department, Cancer Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Jan
authors.initials: J
authors.lastname: Seppälä
authors.affiliation: 2 Department of Medical Physics & Department of Radiotherapy and Oncology, Turku University Hospital, Turku, Finland.
authors.forename: Sami
authors.initials: S
authors.lastname: Suilamo
authors.affiliation: 3 Comprehensive Cancer Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Tenhunen
authors.affiliation: 4 Department of Radiotherapy, North Karelia Central Hospital, Joensuu, Finland.
authors.forename: Liisa
authors.initials: L
authors.lastname: Sailas
authors.affiliation: 1 Radiotherapy Department, Cancer Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Virsunen
authors.affiliation: 3 Comprehensive Cancer Center, Helsinki University Central Hospital, Helsinki, Finland.|5 Lahti Department of Radiotherapy, Tampere University Hospital, Lahti, Finland.
authors.forename: Erna
authors.initials: E
authors.lastname: Kaleva
authors.affiliation: 2 Department of Medical Physics & Department of Radiotherapy and Oncology, Turku University Hospital, Turku, Finland.|3 Comprehensive Cancer Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Jani
authors.initials: J
authors.lastname: Keyriläinen
mesh_terms: D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D058958:Organs at Risk; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011874:Radiometry; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies
keywords: CyberKnife; IMRT; RapidArc; SBRT; VMAT; prostate cancer