Imaging properties of Fe۳O۴@Au and Fe۳O۴@Bi hybrid nanocomposites as contrast agents in spectral X-ray computed tomography: A Monte Carlo simulation study

Objective(s): In this paper, we evaluated some imaging properties of Fe۳O۴@Au and Fe۳O۴@Bi hybrid nanocomposites as contrast agents in spectral CT. For this purpose, we simulated a spectral CT scanner with photon-counting detectors (PCDs) in ۶ energy bins by a Monte Carlo simulator.Materials and Methods: A cylindrical phantom was designed with a diameter of ۸ cm and a height of ۱۰ cm. Fe۳O۴@Au and Fe۳O۴@Bi hybrid nanocomposites were designed as a core-shell with a diameter of ۸۰ nm. Simulation results were utilized to reconstruct cross-sectional images through the filtered back-projection (FBP) algorithm in MATLAB software. Signal intensity and contrast to noise ratio (CNR) of tested contrast agents were calculated in spectral CT images. Results: The results indicated a comparable image quality for Fe۳O۴@Au and Fe۳O۴@Bi hybrid nanocomposites at different energy bins. However, in the energy range of ۸۰ to ۱۲۰ keV (bin ۴ and ۵), the difference in signal intensity and CNR between these two nanocomposites increased. The maximum signal intensity and CNR for Fe۳O۴@Au and Fe۳O۴@Bi were acquired at the highest concentration. The maximum signal intensity for Fe۳O۴@Au was ۱۴۴±۱۰ (HU) in the ۴th energy bin and for Fe۳O۴@Bi ۱۶۲±۱۹ (HU) in the ۵th energy bin. Besides, the maximum CNRs of ۷۴±۶ and ۶۷.۵±۹ for Fe۳O۴@Au in bin ۴, while for Fe۳O۴@Bi in bin ۵ were obtained respectively. Conclusion: Based on our results, Fe۳O۴@Au and Fe۳O۴@Bi hybrid nanocomposites have provided promising results as contrast agents in spectral CT. Fe۳O۴@Bi nanocomposites are recommended due to their lower price and availability.

Keywords:

bismuth nanoparticles , Gold Nanoparticles , Hybrid nanocomposites , Iron oxide nanoparticles , Spectral computed tomography