Sara Khademi - Department of Radiology Technology, School of Paramedical and Rehabilitation Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
Hosein Azimian - Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Hossein Ghadiri - Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran

Introduction: In this study, we aimed to identify the benefits in image contrast enhancement of Folic acid-Cysteamine conjugated gold nanoparticles (FA-Cys-AuNPs) by comparing Contrast to Noise ratio (CNR) of gold nanoparticles (AuNPs) to iodinated compound CT images. The CNR was assessed in different tube voltages, concentrations, and incubation times in nasopharyngeal KB cancer cells. Material and Methods: FA-Cys-AuNPs and Omnipaque suspension were scanned at different concentration ranges (۵۰۰-۲۰۰۰ µg/ml) and energy ranges (۸۰- ۱۴۰ kVp) with CT imaging modality. FA-Cys-AuNPs and AuNPs were incubated in nasopharyngeal cancer cells at different incubation times (۶, ۱۲, and ۲۴ h) and concentration ranges (۲۰۰-۵۰۰ µM). Finally, the contrast enhancement was assessed using CNR value at different tube voltages. Results: Results showed that the formed FA-Cys-AuNPs with an Au core size of ۱۵ nm in all concentrations and tube potentials from ۸۰ to ۱۴۰ kVp display greater CNR than Omnipaque. The CNR value was increased by increasing concentration and energy. At ۱۴۰ kVp and ۲۰۰۰ µg/ml, the CNR value of FA-Cys-AuNPs was ۲.۲۵ times greater than Omnipaque. At ۱۴۰ kVp, ۵۰۰ µM and ۲۴ h incubation, the CNR values of targeted cells were approximately ۱.۵ times higher than non-targeted cells. At ۱۴۰ kVp, and ۵۰۰ µM, the CNR value of targeted cells with ۲۴ h incubation time was ۲.۶۶ times greater than the targeted cells incubated with ۶ h. Conclusion: These findings suggested that the designed FA-Cys-AuNPs could be a good candidate contrast agent for molecular CT imaging.

folic acid, Molecular imaging, CT, Gold Nanoparticle, Cancer