Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2013, Vol. 24 ›› Issue (4): 040204 doi: 10.13538/j.1001-8042/nst.2013.04.004

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A practical image reconstruction and processing method for symmetrically off-center detector CBCT system

HAO Jia1,2  ZHANG Li1,2,*  LI Liang1,2  CHEN Zhiqiang1,2  KANG Kejun1,2   

  1. 1Department of Engineering Physics, Tsinghua University, Beijing 100084, China
    2Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China
  • Received:2012-09-20
  • Contact: ZHANG Li
  • Supported by:

    Supported by National Key Technology R&D Program of the Ministry of Science and Technology (No.2012BAI07B05)

HAO Jia, ZHANG Li, LI Liang, CHEN Zhiqiang, KANG Kejun. A practical image reconstruction and processing method for symmetrically off-center detector CBCT system.Nuclear Science and Techniques, 2013, 24(4): 040204     doi: 10.13538/j.1001-8042/nst.2013.04.004


CBCT scanners have been widely used in angiography, radiotherapy guidance, mammography and oral maxillofacial imaging. To cut detector size, reduce manufacturing costs and radiation dose while keeping a reasonable FOV, the flat panel detector can be placed off-center horizontally. This scanning configuration extends the FOV effectively. However, each projection is transversely truncated, bringing errors and artifacts in reconstruction. In this paper, a simple but practical method is proposed for this scanning geometry based on truncation compensation and the modified FDK algorithm. Numerical simulations with jaw phantom were conducted to evaluate the accuracy and practicability of the proposed method. A novel CBCT system for maxillofacial imaging is used for clinical test, which is equipped with an off-center small size flat panel detector. Results show that reconstruction accuracy is acceptable for clinical use, and the image quality appears sufficient for specific diagnostic requirements. It provides a novel solution for clinical CBCT system, in order to reduce radiation dose and manufacturing cost.

Key words: Cone beam CT, Off-center detector, Image reconstruction, Field of view, Projection truncation, Central artifacts