The application of positron emission tomography/computed tomography in radiation treatment planning: effect on gross target volume definition and treatment management

Clin Oncol (R Coll Radiol). 2010 Apr;22(3):173-8. doi: 10.1016/j.clon.2010.01.003. Epub 2010 Feb 8.


Aims: To analyse the effect of the use of molecular imaging on gross target volume (GTV) definition and treatment management.

Materials and methods: Fifty patients with various solid tumours who underwent positron emission tomography (PET)/computed tomography (CT) simulation for radiotherapy planning from 2006 to 2008 were enrolled in this study. First, F-18 fluorodeoxyglucose (FDG)-PET and CT scans of the treatment site in the treatment position and then a whole body scan were carried out with a dedicated PET/CT scanner and fused thereafter. FDG-avid primary tumour and lymph nodes were included into the GTV. A multidisciplinary team defined the target volume, and contouring was carried out by a radiation oncologist using visual methods. To compare the PET/CT-based volumes with CT-based volumes, contours were drawn on CT-only data with the help of site-specific radiologists who were blind to the PET/CT results after a median time of 7 months.

Results: In general, our PET/CT volumes were larger than our CT-based volumes. This difference was significant in patients with head and neck cancers. Major changes (> or =25%) in GTV delineation were observed in 44% of patients. In 16% of cases, PET/CT detected incidental second primaries and metastatic disease, changing the treatment strategy from curative to palliative.

Conclusions: Integrating functional imaging with FDG-PET/CT into the radiotherapy planning process resulted in major changes in a significant proportion of our patients. An interdisciplinary approach between imaging and radiation oncology departments is essential in defining the target volumes.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Humans
  • Middle Aged
  • Neoplasms / diagnostic imaging*
  • Neoplasms / radiotherapy
  • Positron-Emission Tomography*
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Tomography, X-Ray Computed*
  • Young Adult