title: Treatment planning of stereotactic radiotherapy for solitary lung tumor.
abstract: OBJECTIVE
  To analyze the stereotactic radiotherapy (SRT) plans in terms of internal target volume (ITV) and organs at risk (OARs).
  
  
  METHODS
  Treatment planning and dose distributions were analyzed using dose-volume histograms (DVHs) of ITV and OARs in 37 patients, who were treated for a solitary lung tumor with SRT. The stereotactic body frame (SBF) was used for immobilization and accurate setup. Prescription dose was 48 Gy in four fractions at the isocenter.
  
  
  RESULTS
  Use of SBF limits the extent of the noncoplanar beam directions to prevent a collision with the Linac gantry. DVH analyses showed that the homogeneity index, defined as the ratio of maximum and minimum dose to ITV, ranged from 1.03 to 1.25 (mean, 1.12). The volume irradiated with 20 Gy or more (V(20)) of the lung ranged from 0.3 to 11.6% (mean, 4.4%) of the whole lung volume. The maximum dose to the other OARs ranged from 0 to 11.8 Gy (mean, 0.5-2.7) per fraction. No clinically significant complications were encountered.
  
  
  CONCLUSIONS
  Despite the limitation of the beam arrangement, a homogeneous target dose distribution, while avoiding high doses to normal tissues, was obtained.
authors.affiliation: Department of Therapeutic Radiology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Takayama
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nagata
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Negoro
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizowaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Masato
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Aoki
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yano
authors.forename: Sachiko
authors.initials: S
authors.lastname: Koga
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D001980:Bronchi; D004947:Esophagus; D006321:Heart; D006801:Humans; D008168:Lung; D008175:Lung Neoplasms / Q000601:surgery*; D009010:Monte Carlo Method; D011651:Pulmonary Artery; D011829:Radiation Dosage; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted; D013116:Spinal Cord