Identification of residual metabolic-active areas within NSCLC tumours using a pre-radiotherapy FDG-PET-CT scan: A prospective validation

Hugo J. W. L. Aerts*, Johan Bussink, Wim J. G. Oyen, Wouter van Elmpt, Annemieke M. Folgering, Daisy Emans, Marije Velders, Philippe Lambin, Dirk De Ruysscher

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


It was recently described that high FDG-uptake areas pre-radiotherapy largely correspond with residual metabolic-active areas post-radiotherapy. Here, an independent prospective validation of these results was performed using an overlap-fraction (OF) calculation of various FOG-uptake based thresholds. Data from twelve patients treated at Radboud University Nijmegen Medical Center with lung cancer were analyzed. All patients underwent two FDG-PET-CT scans, one pre-radiotherapy (pre-RT) and one approximately three months after treatment (post-RT). Of the twelve analyzed patients, eight patients showed residual FDG uptake on the post-RT scan and were included for analysis. One of these patients had a residue that was not clearly distinguishable from the surrounding tissue due to FDG avid inflammation. Therefore, seven patients remained for further analysis. The mean volume of the residual metabolic-active areas post-RT was 14.6 +/- 10.0% (mean +/- SD) of the mean volume of the gross tumour volume (GTV) pre-RT. The residual metabolic-active areas largely corresponded with the pre-RT GTV (OF = 93.7 +/- 7.2%). The pre-RT-scan threshold delineations of 34%, 40% and 50% of the SUVmax had a large OF with the residual region, 86.9 +/- 8.3%, 77.4 +/- 8.1% and 67.9 +/- 6.8%, respectively. In this independent dataset, we confirmed that the location of residual FDG-uptake areas after radiotherapy corresponds with the high FDG-uptake areas pre-radiotherapy. Therefore, a pre-radiotherapy FDG-PET-CT scan can potentially be used for radiotherapy dose redistribution.
Original languageEnglish
Pages (from-to)73-76
JournalLung Cancer
Issue number1
Publication statusPublished - Jan 2012


  • Intra-tumour heterogeneity
  • Residual metabolic-activity
  • Residual disease
  • Radio-resistance
  • Lung cancer
  • PET-CT


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