Low-dose cone-beam CT imaging for radiotherapy

Jing Wang, Tianfang Li, Lei Xing

Research output: Chapter in Book/Report/Conference proceedingConference contribution


On-board cone-beam computed tomography (CBCT) provides volumetric information of a patient at treatment position and improves the setup accuracy and may be used for dose reconstruction. However, there is a great concern that repeated use of CBCT during a treatment course delivers too much extra dose to the patient. To reduce the CBCT dose, one needs to lower the total mAs of the x-ray current, which usually leads to reduced image quality. Our goal of this work is to develop an effective method that enables to achieve clinically acceptable CBCT image with as low as possible mAs without compromising quality. An iterative image reconstruction algorithm based on a penalized weighted least-squares (PWLS) principle was developed for this purpose. To preserve edges in the reconstructed images, we designed an anisotropic penalty term of a quadratic form. The algorithm was evaluated with a CT quality assurance phantom and an anthropomorphic head phantom. Compared with conventional isotropic penalty, the PWLS image reconstruction algorithm with anisotropic penalty shows better resolution preservation.

Original languageEnglish (US)
Title of host publicationWorld Congress on Medical Physics and Biomedical Engineering
Subtitle of host publicationRadiation Oncology
PublisherSpringer Verlag
Number of pages4
ISBN (Print)9783642034725
StatePublished - 2009
EventWorld Congress on Medical Physics and Biomedical Engineering: Radiation Oncology - Munich, Germany
Duration: Sep 7 2009Sep 12 2009

Publication series

NameIFMBE Proceedings
ISSN (Print)1680-0737


OtherWorld Congress on Medical Physics and Biomedical Engineering: Radiation Oncology


  • Cone-beam CT
  • Edge-preserving penalty
  • Iterative reconstruction
  • Low-dose
  • PWLS

ASJC Scopus subject areas

  • Bioengineering
  • Biomedical Engineering


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