Raw data normalization for a multi source inverse geometry CT system

Jongduk Baek, Bruno De Man, Daniel Harrison, Norbert J. Pelc

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A multi-source inverse-geometry CT (MS-IGCT) system consists of a small 2D detector array and multiple X-ray sources. During data acquisition, each source is activated sequentially, and may have random source intensity fluctuations relative to their respective nominal intensity. While a conventional 3rd generation CT system uses a reference channel to monitor the source intensity fluctuation, the MS-IGCT system source illuminates a small portion of the entire field-of-view (FOV). Therefore, it is difficult for all sources to illuminate the reference channel and the projection data computed by standard normalization using flat field data of each source contains error and can cause significant artifacts. In this work, we present a raw data normalization algorithm to reduce the image artifacts caused by source intensity fluctuation. The proposed method was tested using computer simulations with a uniform water phantom and a Shepp-Logan phantom, and experimental data of an ice-filled PMMA phantom and a rabbit. The effect on image resolution and robustness of the noise were tested using MTF and standard deviation of the reconstructed noise image. With the intensity fluctuation and no correction, reconstructed images from simulation and experimental data show high frequency artifacts and ring artifacts which are removed effectively using the proposed method. It is also observed that the proposed method does not degrade the image resolution and is very robust to the presence of noise.

Original languageEnglish
Pages (from-to)7514-7526
Number of pages13
JournalOptics Express
Volume23
Issue number6
DOIs
Publication statusPublished - 2015 Mar 23

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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