Target volume delineation variation in radiotherapy for early stage rectal cancer in the Netherlands

Jasper Nijkamp, Danielle F. M. de Haas-Kock, Jannet C. Beukema, Karen J. Neelis, Dankert Woutersen, Heleen Ceha, Tom Rozema, Annerie Slot, Hanneke Vos-Westerman, Martijn Intven, Patty H. Spruit, Yvette van der Linden, Debby Geijsen, Karijn Verschueren, Marcel B. van Herk, Corrie A. M. Marijnen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


The aim of this study was to measure and improve the quality of target volume delineation by means of national consensus on target volume definition in early-stage rectal cancer.The CTV's for eight patients were delineated by 11 radiation oncologists in 10 institutes according to local guidelines (phase 1). After observer variation analysis a workshop was organized to establish delineation guidelines and a digital atlas, with which the same observers re-delineated the dataset (phase 2). Variation in volume, most caudal and cranial slice and local surface distance variation were analyzed.The average delineated CTV volume decreased from 620 to 460 cc (p
Original languageEnglish
Pages (from-to)14-21
JournalRadiotherapy and Oncology
Issue number1
Publication statusPublished - Jan 2012


  • Delineation variation
  • Rectal cancer
  • Delineation atlas
  • Clinical target volume

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