Gold Nanoparticle Contrast in a Phantom and Juvenile Swine: Models for Molecular Imaging of Human Organs using X-ray Computed Tomography

Rationale and Objectives: The purpose of this study was to demonstrate the application of gold nanoparticles (AuNP) as a contrast agent for a clinical x-ray computed tomography (CT) system using a phantom and juvenile swine. Materials and Methods: A tissue-mimicking phantom with spherical inclusions containing known concentrations of Au was scanned. Swine were injected with gum Arabic stabilized Au nanoparticles (GA-AuNP), up to 85 mg kg(-1) body weight. CT scans were performed before and after the injections. Changes in Hounsfield unit (HU) values between pre- and post- injection scans were evaluated and compared to postmortem determinations of Au uptake. Average uptake of GA-AuNP in the liver of the swine was 380 mu g per gram of liver and 680 mu g per gram of spleen. Results: Concentrations of Au in tissues increased the CT numbers in liver by approximately 22 HU per mg Au concentration at 80 kVp and 27 HU per mg Au concentration at 140 kVp. These data were consistent with HU changes observed for similar concentrations in the phantom. Conclusions: AuNP-based contrast agents may be useful in x-ray based CT. This study provides data for determining concentrations of AuNP in comparison to other contrast materials.