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

Lung Cancer. 2012 Jan;75(1):73-6. doi: 10.1016/j.lungcan.2011.06.003. Epub 2011 Jul 22.


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 FDG-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 SUV(max) 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Carcinoma, Non-Small-Cell Lung / diagnostic imaging*
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / radiotherapy*
  • Chemoradiotherapy / methods
  • Cisplatin / administration & dosage
  • Deoxycytidine / administration & dosage
  • Deoxycytidine / analogs & derivatives
  • Fluorodeoxyglucose F18* / pharmacokinetics
  • Humans
  • Lung Neoplasms / diagnostic imaging*
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / radiotherapy*
  • Middle Aged
  • Positron-Emission Tomography / methods
  • Prospective Studies
  • Radiopharmaceuticals / pharmacokinetics
  • Radiotherapy Planning, Computer-Assisted
  • Tomography, X-Ray Computed / methods*
  • Tumor Burden / radiation effects


  • Radiopharmaceuticals
  • Deoxycytidine
  • Fluorodeoxyglucose F18
  • gemcitabine
  • Cisplatin