Application of asymmetric cone-beam CT in radiotherapy

Lifeng Yu, Charles Pelizzari, Xiaochuan Pan, Heinrich Riem, Peter Munro, Wolfgang Kaissl

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations


In many implementations of cone-beam CT in radiotherapy for target positioning, it is not uncommon that the maximum allowable field of view (FOV) cannot cover the patient because of the limited size of the flat-panel detector. In this situation, the measurements will contain truncated projections, leading to significant artifacts in reconstructed images. Asymmetric conebeam configurations can be used for increasing the FOV size by displacing the detector panel to one side. From the data acquired with such an asymmetric configuration, the well-known algorithm developed by Feldkamp, Davis, and Kress (FDK) can be modified to reconstruct images. With increasing detector asymmetry, however, the modified FDK algorithm may produce significant aliasing artifacts. In this work, we develop a novel algorithm for image reconstruction in asymmetric cone-beam CT, which can generate images with improved numerical properties and allow for large detector asymmetry. We have employed the asymmetric configuration and the developed algorithm in a cone-beam CT system in radiotherapy to increase the FOV size. Preliminary phantom studies have been conducted to validate the asymmetric configuration and the proposed reconstruction algorithm.

Original languageEnglish (US)
Article numberM5-458
Pages (from-to)3249-3252
Number of pages4
JournalIEEE Nuclear Science Symposium Conference Record
StatePublished - Dec 1 2004
Event2004 Nuclear Science Symposium, Medical Imaging Conference, Symposium on Nuclear Power Systems and the 14th International Workshop on Room Temperature Semiconductor X- and Gamma- Ray Detectors - Rome, Italy
Duration: Oct 16 2004Oct 22 2004


  • Computed tomography (CT)
  • Cone-beam CT
  • Image reconstruction
  • Radiation therapy

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging


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