Trial Information

The trial aims to evaluate the utility of 18FDG-PET/CT in SBRT planning for NSCLC with
particular emphasis on the definition of macroscopic and microscopic boundaries of malignant
growth. Studies indicate that the definition of the gross tumor volume may gain in quality
when CT and 18FDG-PET are combined. In about 30-60% of NSCLC patients considered for
radiotherapy, alteration of CT-based treatment volumes is the consequence of a supplementary
18FDG-PET scan. Studies examining the effect of combined PET/CT scans on the delineation of
the GTV generally show reduced intra- and inter-clinician variability. Whether this higher
degree of consistency is an actual improvement remains to be proven. Pathological specimens
from operated NSCLC patients may serve as a gold standard in this respect. To meet the need
for tight margins, the clinical target volume in SBRT planning is generally presumed to
correspond to the GTV. Whether this clinical practice rests on firm ground is also an issue
that can be addressed in a PET-CT-pathology correlation study.