Identification of residual metabolic-active areas within individual NSCLC tumours using a pre-radiotherapy (18)Fluorodeoxyglucose-PET-CT scan

Radiother Oncol. 2009 Jun;91(3):386-92. doi: 10.1016/j.radonc.2009.03.006. Epub 2009 Mar 28.


Background and purpose: Non-small cell lung cancer (NSCLC) tumours are mostly heterogeneous. We hypothesized that areas within the tumour with a high pre-radiation (18)F-deoxyglucose (FDG) uptake, could identify residual metabolic-active areas, ultimately enabling selective-boosting of tumour sub-volumes.

Material and methods: Fifty-five patients with inoperable stage I-III NSCLC treated with chemo-radiation or with radiotherapy alone were included. For each patient one pre-radiotherapy and one post-radiotherapy FDG-PET-CT scans were available. Twenty-two patients showing persistent FDG uptake in the primary tumour after radiotherapy were analyzed. Overlap fractions (OFs) were calculated between standardized uptake value (SUV) threshold-based auto-delineations on the pre- and post-radiotherapy scan.

Results: Patients with residual metabolic-active areas within the tumour had a significantly worse survival compared to individuals with a complete metabolic response (p=0.002). The residual metabolic-active areas within the tumour largely corresponded (OF>70%) with the 50%SUV high FDG uptake area of the pre-radiotherapy scan. The hotspot within the residual area (90%SUV) was completely within the GTV (OF=100%), and had a high overlap with the pre-radiotherapy 50%SUV threshold (OF>84%).

Conclusions: The location of residual metabolic-active areas within the primary tumour after therapy corresponded with the original high FDG uptake areas pre-radiotherapy. Therefore, a single pre-treatment FDG-PET-CT scan allows for the identification of residual metabolic-active areas.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Non-Small-Cell Lung / diagnostic imaging
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Carcinoma, Non-Small-Cell Lung / radiotherapy
  • Female
  • Fluorodeoxyglucose F18 / pharmacokinetics*
  • Humans
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology
  • Lung Neoplasms / radiotherapy
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Positron-Emission Tomography
  • Proportional Hazards Models
  • Radiopharmaceuticals / pharmacokinetics*
  • Radiotherapy Planning, Computer-Assisted
  • Statistics, Nonparametric
  • Survival Rate
  • Tomography, X-Ray Computed
  • Treatment Outcome


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18