title: Impact of 4D-(18)FDG-PET/CT imaging on target volume delineation in SBRT patients with central versus peripheral lung tumors. Multi-reader comparative study.
abstract: OBJECTIVE
  Evaluation of the effect of co-registered 4D-(18)FDG-PET/CT for SBRT target delineation in patients with central versus peripheral lung tumors.
  
  
  METHODS
  Analysis of internal target volume (ITV) delineation of central and peripheral lung lesions in 21 SBRT-patients. Manual delineation was performed by 4 observers in 2 contouring phases: on respiratory gated 4DCT with diagnostic 3DPET available aside (CT-ITV) and on co-registered 4DPET/CT (PET/CT-ITV). Comparative analysis of volumes and inter-reader agreement.
  
  
  RESULTS
  11 cases of peripheral and 10 central lesions were evaluated. In peripheral lesions, average CT-ITV was 6.2 cm(3) and PET/CT-ITV 8.6 cm(3), resembling a mean change in hypothetical radius of 2 mm. For both CT-ITVs and PET/CT-ITVs inter reader agreement was good and unchanged (0.733 and 0.716; p=0.58). All PET/CT-ITVs stayed within the PTVs derived from CT-ITVs. In central lesions, average CT-ITVs were 42.1 cm(3), PET/CT-ITVs 44.2 cm(3), without significant overall volume changes. Inter-reader agreement improved significantly (0.665 and 0.750; p<0.05). 2/10 PET/CT-ITVs exceeded the PTVs derived from CT-ITVs by >1 ml in average for all observers.
  
  
  CONCLUSIONS
  The addition of co-registered 4DPET data to 4DCT based target volume delineation for SBRT of centrally located lung tumors increases the inter-observer agreement and may help to avoid geographic misses.
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Alin
authors.initials: A
authors.lastname: Chirindel
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Adebahr
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schuster
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Schimek-Jasch
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Schanne
authors.affiliation: Department of Nuclear Medicine, University Medical Center Freiburg, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Nemer
authors.affiliation: Department of Nuclear Medicine, University Medical Center Freiburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Mix
authors.affiliation: Department of Nuclear Medicine, University Medical Center Freiburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Meyer
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Anca-Ligia
authors.initials: AL
authors.lastname: Grosu
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Partner Site Freiburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Brunner
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Germany; German Cancer Consortium (DKTK), Heidelberg, Partner Site Freiburg, Germany. Electronic address: ursula.nestle@uniklinik-freiburg.de.
authors.forename: Ursula
authors.initials: U
authors.lastname: Nestle
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography / Q000379:methods
keywords: 4DPET/CT; Central lung tumors; SBRT; Target volume delineation