Image quality and stability of image-guided radiotherapy (IGRT) devices: A comparative study

Markus Stock*, Marlies Pasler, Wolfgang Birkfellner, Peter Homolka, Richard Poetter, Dietmar Georg

*Corresponding author for this work

Research output: Journal article (peer-reviewed)Journal article

70 Citations (Scopus)


INTRODUCTION: Our aim was to implement standards for quality assurance of IGRT devices used in our department and to compare their performances with that of a CT simulator.

MATERIALS AND METHODS: We investigated image quality parameters for three devices over a period of 16months. A multislice CT was used as a benchmark and results related to noise, spatial resolution, low contrast visibility (LCV) and uniformity were compared with a cone beam CT (CBCT) at a linac and simulator.

RESULTS: All devices performed well in terms of LCV and, in fact, exceeded vendor specifications. MTF was comparable between CT and linac CBCT. Integral nonuniformity was, on average, 0.002 for the CT and 0.006 for the linac CBCT. Uniformity, LCV and MTF varied depending on the protocols used for the linac CBCT. Contrast-to-noise ratio was an average of 51% higher for the CT than for the linac and simulator CBCT. No significant time trend was observed and tolerance limits were implemented.

DISCUSSION: Reasonable differences in image quality between CT and CBCT were observed. Further research and development are necessary to increase image quality of commercially available CBCT devices in order for them to serve the needs for adaptive and/or online planning.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalRadiotherapy and Oncology
Issue number1
Publication statusPublished - Oct 2009
Externally publishedYes


  • Artifacts
  • Computer Simulation
  • Cone-Beam Computed Tomography/instrumentation
  • Contrast Media
  • Equipment Design
  • Equipment Safety
  • Humans
  • Phantoms, Imaging
  • Radiation Oncology/instrumentation
  • Radiographic Image Interpretation, Computer-Assisted/instrumentation
  • Radiography, Interventional
  • Radiotherapy Planning, Computer-Assisted/instrumentation
  • Radiotherapy, Computer-Assisted/instrumentation
  • Radiotherapy, Conformal/instrumentation
  • Tomography, X-Ray Computed/instrumentation
  • Total Quality Management


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