High-Perform Yb-Based Nanoparticulate X-Ray CT Contrast Agent

Abstract

X-ray computed tomography (CT) has been considered to be the most powerful diagnostic tool in clinical diagnosis due to its many advantages compared to other molecular imaging. X-ray CT contrast agents currently used in clinic scanning are mainly based on iodinated small molecules. However, these small molecules suffer from many disadvantages, such as low contrast efficiency, very short circulation lifetime, and potential renal toxicity. Moreover, some patients are hypersensitive to iodine. These disadvantages have significantly restricted the applications of X-ray CT in biomedicine, particularly in targeted imaging. In this chapter, we describe a first-in-class Yb-based nanoparticulate CT contrast agent. Owing to the attenuation characteristics of Yb, which is matched with the X-ray photon energy used in clinical applications, the Yb-based nanoparticulate CT contrast agent offers a much higher contrast efficacy compared to the clinical iodinated agent at 120 kVp. Along with long circulation time and low toxicity in vivo, these nanoparticles can act as a high-performance CT contrast agent for in vivo angiography and bimodal imageguided lymph node mapping. By doping Gd into the nanoparticles, this contrast agent also shows enhanced upconversion luminescence and MRI capability.