title: Comparison and consensus guidelines for delineation of clinical target volume for CT- and MR-based brachytherapy in locally advanced cervical cancer.
abstract: OBJECTIVE
  To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy.
  
  
  METHODS
  Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case.
  
  
  RESULTS
  For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR.
  
  
  CONCLUSIONS
  In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx.
authors.affiliation: Brigham & Women's Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts. Electronic address: aviswanathan@lroc.harvard.edu.
authors.forename: Akila N
authors.initials: AN
authors.lastname: Viswanathan
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Beth
authors.initials: B
authors.lastname: Erickson
authors.affiliation: University of Utah Huntsman Cancer Hospital, Salt Lake City, Utah.
authors.forename: David K
authors.initials: DK
authors.lastname: Gaffney
authors.affiliation: University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania.
authors.forename: Sushil
authors.initials: S
authors.lastname: Beriwal
authors.affiliation: University of Iowa, Iowa City, Iowa.
authors.forename: Sudershan K
authors.initials: SK
authors.lastname: Bhatia
authors.affiliation: University of Alabama, Birmingham, Alabama.
authors.forename: Omer
authors.initials: O
authors.lastname: Lee Burnett
authors.affiliation: London Health Sciences Centre and Western University, London, Ontario, Canada.
authors.forename: David P
authors.initials: DP
authors.lastname: D'Souza
authors.affiliation: London Health Sciences Centre and Western University, London, Ontario, Canada.
authors.forename: Nikhilesh
authors.initials: N
authors.lastname: Patil
authors.affiliation: Mayo Medical Center, Rochester, Minnesota.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Haddock
authors.affiliation: University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Anuja
authors.initials: A
authors.lastname: Jhingran
authors.affiliation: University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Jones
authors.affiliation: Case Western Reserve University, Cleveland, Ohio.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Kunos
authors.affiliation: Brigham & Women's Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Larissa J
authors.initials: LJ
authors.lastname: Lee
authors.affiliation: University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Lilie L
authors.initials: LL
authors.lastname: Lin
authors.affiliation: University of Washington, Seattle, Washington.
authors.forename: Nina A
authors.initials: NA
authors.lastname: Mayr
authors.affiliation: Mayo Medical Center, Rochester, Minnesota.
authors.forename: Ivy
authors.initials: I
authors.lastname: Petersen
authors.affiliation: Division of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia; Department of Radiation Oncology, National Center for Cancer Care and Research, Doha, Qatar.
authors.forename: Primoz
authors.initials: P
authors.lastname: Petric
authors.affiliation: University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Portelance
authors.affiliation: Loyola University Strich School of Medicine, Chicago, Illinois.
authors.forename: William
authors.initials: W
authors.lastname: Small
authors.affiliation: The Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illinois.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Strauss
authors.affiliation: Brigham & Women's Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Kanokpis
authors.initials: K
authors.lastname: Townamchai
authors.affiliation: University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Aaron H
authors.initials: AH
authors.lastname: Wolfson
authors.affiliation: University of California, San Diego, California, Washington University, St. Louis, Missouri.
authors.forename: Catheryn M
authors.initials: CM
authors.lastname: Yashar
authors.affiliation: Washington University, St. Louis, Missouri.
authors.forename: Walter
authors.initials: W
authors.lastname: Bosch
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D032921:Consensus; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D018365:Neoplasm, Residual; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000532:radiotherapy