Defining target volumes for stereotactic ablative radiotherapy of early-stage lung tumours: a comparison of three-dimensional 18F-fluorodeoxyglucose positron emission tomography and four-dimensional computed tomography. PETCT versus 4DCT for SABR in Early Stage NSCLC

Gerard Hanna, John van Sornsen de Koste, Max Dahale, Katherine Carson, Cornelius Haasbeek, Remmelt Migchielsen, Alan Hounsell, Suresh Senan

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

AIMS: High local control rates are achieved in stage I lung cancer using
stereotactic ablative radiotherapy. Target delineation is commonly based on
four-dimensional computed tomography (CT) scans. Target volumes defined by
positron emission tomography/computed tomography (PET/CT) are compared with those defined by four-dimensional CT and conventional ('three-dimensional')
(18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT.

MATERIALS AND METHODS: For 16 stage I non-small cell lung cancer tumours, six
approaches for deriving PET target volumes were evaluated: manual contouring,
standardised uptake value (SUV) absolute threshold of 2.5, 35% of maximum SUV
(35%SUV(MAX)), 41% of SUV(MAX) (41%SUV(MAX)) and two different source to
background ratio techniques (SBR-1 and SBR-2). PET-derived target volumes were compared with the internal target volume (ITV) from the modified maximum
intensity projection (MIP(MOD) ITV). Volumetric and positional correlation was
assessed using the Dice similarity coefficient (DSC).

RESULTS: PET-based target volumes did not correspond to four-dimensional CT-based target volumes. The mean DSC relative to MIP(MOD) ITV were: PET manual = 0.64, SUV2.5 = 0.64, 35%SUV(MAX) = 0.63, 41%SUV(MAX) = 0.57. SBR-1 = 0.52, SBR-2 =0.49. PET-based target volumes were smaller than corresponding MIP ITVs.

CONCLUSIONS: Conventional three-dimensional (18)F-FDG PET-derived target volumes for lung stereotactic ablative radiotherapy did not correspond well with those derived from four-dimensional CT, including those in routine clinical use
(MIP(MOD) ITV). Caution is required in using three-dimensional PET for motion
encompassing target volume delineation.
Original languageEnglish
Pages (from-to)e71-80
Number of pages10
JournalClinical oncology (Royal College of Radiologists (Great Britain))
Volume24
Issue number6
Early online date24 Mar 2012
DOIs
Publication statusPublished - 01 Aug 2012

Keywords

  • PET/CT
  • 4DCT
  • SABR
  • Stereotactic
  • Lung Cancer

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

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