Tilted helical Feldkamp cone-beam reconstruction algorithm for multislice CT

Ilmar A. Hein, Katsuyuki Taguchi, Issei Mori, Masahiro Kazama, Michael D. Silver

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations

Abstract

In many clinical applications, it is necessary to tilt the gantry of an X-ray CT system with respect to the patient. Tilting the gantry introduces no complications for single-slice fan-beam systems; however, most systems today are helical multislice systems with up to 16 slices (and this number is sure to increase in the future). The image reconstruction algorithms used in multislice helical CT systems must be modified to compensate for the tilt. If they are not, the quality of reconstructed images will be poor with the presence of significant artifacts produced by the tilt. Practical helical multislice algorithms currently incorporated in today's systems include helical fan-beam, ASSR (Advanced single-slice rebinning), and Feldkamp algorithms. This paper presents the modifications necessary to compensate for gantry tilt for the helical cone-beam Feldkamp algorithm implemented by Toshiba (referred to as TCOT for true cone-beam tomography). Unlike some of the other algorithms, gantry tilt compensation is simple and straightforward to implement with no significant increase in computational complexity. It will be shown that the effect of the gantry tilt is to introduce a lateral shift in the isocenter of the reconstructed slice of interest, which is a function of the tilt, couch speed, and view angle. This lateral shift is easily calculated and incorporated into the backprojection algorithm. The tilt-compensated algorithm is called T-TCOT. Experimental tilted-gantry data has been obtained with 8- and 16 slice Toshiba Aquilion systems, and examples of uncompensated and tilt compensated images are presented.

Original languageEnglish (US)
Pages (from-to)1901-1910
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume5032 III
DOIs
StatePublished - 2003
Externally publishedYes
EventMedical Imaging 2003: Image Processing - San Diego, CA, United States
Duration: Feb 17 2003Feb 20 2003

Keywords

  • CT
  • Cone-beam
  • Feldkamp
  • Helical
  • Multislice
  • T-TCOT
  • TCOT
  • Tilted gantry
  • X-ray

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'Tilted helical Feldkamp cone-beam reconstruction algorithm for multislice CT'. Together they form a unique fingerprint.

Cite this