The integration of PET-CT scans from different hospitals into radiotherapy treatment planning

Radiother Oncol. 2008 Apr;87(1):142-6. doi: 10.1016/j.radonc.2007.12.025. Epub 2008 Jan 22.


Purpose: To integrate PET-CT scans from different hospitals into radiotherapy treatment planning.

Methods and materials: A cylindrical phantom with spheres of different diameters was scanned on three different Siemens Biograph PET-CT scanners in three hospitals. The spheres and cylinder were filled with 18F-FDG such that different sphere-to-background (S/B) ratios were obtained. Scans were analyzed using dedicated software for automated delineation based on standardized uptake value (SUV) and using different reconstruction parameters.

Results: SUV thresholding curves for different S/B ratios were obtained for the different scanners. Differences in SUV auto-contouring thresholds were found to be significant for PET-CT simulators from different radiotherapy and nuclear medicine departments. A change in PET reconstruction parameters showed a significant effect on the results.

Conclusion: Synchronization of PET-CT imaging protocols between cooperating hospitals is important for reliable determination of SUV auto-contouring thresholds. Whenever this goal has been achieved automated SUV delineation based on a S/B ratio using PET-CT images from different institutions can reliably be performed using individually determined threshold curves.

Publication types

  • Multicenter Study

MeSH terms

  • Fluorodeoxyglucose F18
  • Humans
  • Image Interpretation, Computer-Assisted / methods*
  • Phantoms, Imaging
  • Radiopharmaceuticals
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Regression Analysis
  • Software
  • Tomography, Emission-Computed*
  • Tomography, X-Ray Computed*


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18