title: Variations in target volume definition and dose to normal tissue using anatomic versus biological imaging (18F-FDG-PET) in the treatment of bone metastases: results from a 3-arm randomized phase II trial.
abstract: BACKGROUND
  To report the impact on target volume delineation and dose to normal tissue using anatomic versus biological imaging (18F-FDG-PET) for bone metastases.
  
  
  METHODS
  Patients with uncomplicated painful bone metastases were randomized (1:1:1) and blinded to receive either 8 Gy in a single fraction with conventionally planned radiotherapy (ConvRT-8 Gy) or 8 Gy in a single fraction with dose-painting-by-numbers (DPBN) dose range between 6 and 10 Gy) (DPBN-8 Gy) or 16 Gy in a single fraction with DPBN (dose range between 14 and 18 Gy) (DPBN-16 Gy). The primary endpoint was overall pain response at 1 month. Volumes of the gross tumour volume (GTV) - both biological (GTVPET) and anatomical (GTVCT) -, planning target volume (PTV), dose to the normal tissue and maximum standardized-uptake values (SUVMAX) were analysed (secondary endpoint).
  
  
  RESULTS
  Sixty-three percent of the GTVCTvolume did not show18F-FDG-uptake. On average, 20% of the GTVPETvolume was outside GTVCT. The volume of normal tissue receiving 4 Gy, 6 Gy and 8 Gy was at least 3×, 6× and 13× smaller in DPBN-8 Gy compared to ConvRT-8 Gy and DPBN-16 Gy (P < 0.05).
  
  
  CONCLUSIONS
  Positron emitting tomography-information potentially changes the target volume for bone metastases. DPBN between 6 and 10 Gy significantly decreases dose to the normal tissue compared to conventional radiotherapy.
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.|Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Dieter
authors.initials: D
authors.lastname: Berwouts
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: De Wolf
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: Wilfried
authors.initials: W
authors.lastname: De Neve
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: Luiza Am
authors.initials: LA
authors.lastname: Olteanu
authors.affiliation: Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Bieke
authors.initials: B
authors.lastname: Lambert
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: Bruno
authors.initials: B
authors.lastname: Speleers
authors.affiliation: Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Goethals
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: Indira
authors.initials: I
authors.lastname: Madani
authors.affiliation: Department of Radiotherapy, Ghent University Hospital, Ghent, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Ost
mesh_terms: D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000532:radiotherapy*; D049268:Positron-Emission Tomography / Q000379:methods*; D015642:Radiology, Interventional / Q000379:methods*; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: bone metastasis; dose-painting-by-numbers; palliative treatment; stereotactic body radiotherapy; volume analysis