Simulation Research of Multi-Pinhole Collimated L-Shell XFCT Imaging System

Yan Luo,Peng Feng,Jing Guo,Peng He,Biao Wei,Ruge Zhao

doi:10.1109/access.2020.3028066

Yan Luo, Peng Feng + Show 4 more

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https://doi.org/10.1109/access.2020.3028066

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Abstract

Polychromatic source X-ray fluorescence computed tomography (XFCT) is a novel imaging method, which is applied for the diagnosis and treatment studies of early stage cancer. In this paper, we propose a fast multi-pinhole L-shell XFCT imaging system to reduce the scan time and radiation dose, which has potential in detecting lower concentration of contrast agents (gold nanoparticles, GNPs). Two kinds of phantoms - the concentration-phantom 1 and the size-phantom 2 are designed to verify imaging performance for low-concentration and small-size ROI. The scanning processes are simulated by Geant4, and images are reconstructed by Optimized EM-TV algorithm. It is concluded that this imaging system is more sensitive in detecting low concentration GNPs than K-shell imaging system. Simulation experiments show the reconstructed images can achieve the highest CNR both for phantom 1 and phantom 2 with iterating 10 times. The detection limit can reach 0.16% when pinhole radius is 0.08mm.

Highlights

X-ray fluorescence computed tomography(XFCT)is a novel way to detect early stage cancer, combined X-ray computed tomography(X-CT) with X-ray fluorescence analysis(XRF) [1]–[3]
XFCT IMAGING THEORY XFCT can be seen as a stimulated emission tomography, in which a sample is irradiated with X-rays more energetic than the K-shell energy of the target elements of interest
The effective particle ratio is as high as 0.9013, which is much higher than K-shell XFCT [18]

Summary

Introduction

X-ray fluorescence computed tomography(XFCT)is a novel way to detect early stage cancer, combined X-ray computed tomography(X-CT) with X-ray fluorescence analysis(XRF) [1]–[3]. In 1996, Takeda et al introduced the principle of XFCT in detail and measured the distribution of iodine in mice with a synchrotron radiation source [5]. The previous experiments were all based on synchrotron radiation source. In recent years, they have turned to conventional X-ray tube source. Cong et al successfully reconstructed the concentration of GNPs from 0.2% to 0.5% by using fan beam X-ray tube source and parallel single-hole collimation [6]. Deng et al used conventional X-ray tube source detected the distribution of GNPs in mouse kidney [7]

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