Advancements in infrared imaging platforms: complementary imaging systems and contrast agents.

Recent advancements in the infrared (IR) imaging system design as well as the co-development of compatible contrast agents have facilitated the potential application of fluorescence imaging systems for deep tissue diagnostics and real-time vasculature visualization for intraoperative surgical guidance. Compared to conventional imaging techniques that achieve superior tissue penetration depth through the use of high energy or ionizing radiation sources, complementary chemical compounds, also known as imaging probes or contrast agents, are required to enable enhancement of the imaging sensitivity required for improved image quality in the IR fluorescence imaging technique. Therefore, using a systems-level approach to plan research efforts where the requirements of the imaging setup are considered at the start of the contrast agent design to effectively improve detection sensitivity would reduce the technical entry barrier for the adoption of new technologies. In this paper, we highlight (1) the recent advancements and key operating differences in the reported IR imaging systems, and (2) the recent progress in creating biocompatible IR-emitting contrast agents as well as improving detection sensitivity using targeting agents. The ability to maximize the full benefits and performance of any IR imaging platform is highly reliant on the thorough understanding of the requirements of each imaging platform and the physical characteristics of the complementary contrast agents.