Computed tomography, or CT, was developed in 1960s and early 1970s. It refers to a computerized X-ray imaging procedure in which a narrow beam of X-rays is aimed at the patient and rapidly revolves around the body, producing signals that are processed by a machine computer to generate a cross-sectional image of the body. CT images are reconstructed from this dataset by computers using algorithms.

Contrast agents for CT?

Small iodinated molecules are commonly used as CT contrast agents, but these contrast agents typically undergo rapid renal excretion and allow very short time imaging. To better address these issues, iodine-based nanoparticles, such as nanoemulsions, liposomes and polymer nanoparticles, are developed to increase particle size and avoid renal filtration. However, iodine-based contrast agents were found hazardous to the environment and some patients have iodine in tolerance due to thyroid origin diseases. Scientists from different fields try to develop contrast agents which can be an alternative to iodine-based contrast agents.

Metallic nanoparticles have potential to be used as CT contrast agent since metals has high X-ray attenuation and high density. Metal nanoparticles considered as toxic to the living organisms. Covering nanoparticles with organic molecule often reduce toxicity and enhance the biocompatibility. Decoration of nanoparticles with function groups give them targeting properties where special organ and/or tissue can be targeted. Up to now, different studies illustrated the importance of the multipurpose properties of the metallic nanoparticles. These metal nanoparticles include Au, Bi, Ta, and Yb.

What are the advantages of using nanoparticles as contrast agents for CT?

Nanoparticle contrast agents for CT have several exciting advantages. A feature of nanoparticles is that their circulation half-lives have been reported to be as long as 15 hours, whereas that of iodinated molecules is only minutes. CT contrast agents that circulate for a long time could be used in applications where repeated injection of iodine contrast agents is required, such as for stent placement. Nanoparticles can be used to allow cell tracking in vivo.

Targeted nanoparticle CT contrast agents can detect the expression of proteins or cell types in tissues, for example detecting the macrophage content of atherosclerotic plaque. Nanoparticles can also be used with emerging CT techniques, such as spectral CT, which can specifically detect exogenous contrast agents.

Additionally, nanoparticles can be multifunctional and so can provide contrast for multiple imaging modalities, e.g. CT, MRI and fluorescence, or provide therapeutic effects as well as CT contrast. Last, nanoparticles may be compatible with patients for whom conventional iodinated contrast media is contraindicated due to renal insufficiency or allergic responses.

CT contrast agents for your research?

With years of experience in nanoparticle preparation and imaging contrast agent development, CD Bioparticles offers the broadest range of CT contrast agents, including iodine-based nanoparticles and metal nanoparticles. We provide customized in vivo target-specific contrast agents for preclinical micro-CT in small animals. We also offer bioconjugation services to manufacture target-specific contrast agents based on your unique requirements. Our extensive knowledge enables us to design and construct nanoparticle-based contrast agents tailored for micro-CT.

1. Aslan, N., Ceylan, B., Koç, M. M., & Findik, F. (2020). Metallic nanoparticles as X-Ray computed tomography (CT) contrast agents: A review. Journal of Molecular Structure, 1219, 128599.
2. Cormode, D. P., Naha, P. C., & Fayad, Z. A. (2014). Nanoparticle contrast agents for computed tomography: a focus on micelles. Contrast media & molecular imaging, 9(1), 37-52.

Author's Bio: 

CD Bioparticles is a leading manufacturer and supplier of various nanoparticles, microparticles and their coatings for R&D and commercialization in a wide variety of application areas including in-vitro diagnostics, biochemistry, cellular analysis, cell separation, immunoassay.