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Low-Dose Cone-Beam CT Imaging for Radiotherapy

  • Jing Wang
  • Tianfang Li
  • Lei Xing
Conference paper
Part of the IFMBE Proceedings book series (IFMBE, volume 25/1)

Abstract

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.

Keywords

cone-beam CT low-dose iterative reconstruction PWLS edge-preserving penalty 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Jing Wang
    • 1
  • Tianfang Li
    • 2
  • Lei Xing
    • 1
  1. 1.Department of Radiation OncologyStanford University School of MedicineStanfordUSA
  2. 2.Department of Radiation OncologyUniversity of Pittsburg Cancer InstitutePittsburgUSA

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