Nuclear and Optical Bimodal Imaging Probes Using Sequential Assembly: A Perspective

Abstract

New, targeted imaging tracers enable improved diagnosis, staging, and planning of treatment of disease and represent an important step toward personalized medicine applications. The combination of radioisotopes for nuclear imaging with fluorophores for fluorescence imaging provides the possibility to noninvasively assess disease burden in a patient using positron emission tomography/single-photon emission computed tomography, followed by fluorescence imaging-assisted surgical intervention in close succession. Probes enabling imaging with both modalities pose a design, synthesis, and pharmacokinetics challenge. In this study, the authors strive to summarize recent efforts toward optimized, discrete, bimodal probes as well as a perspective on future directions of this burgeoning subfield of targeted imaging probe development.

Keywords: fluorophores; molecular imaging; multimodality; radioisotopes.

FIG. 1.

Schematic description of common multimodal probe design strategies based on linkage of individual components (radioisotope with prosthetic group/chelator, fluorophore, and targeting vector) discussed in this perspective.

FIG. 2.

Antibody-linked multimodal probe approaches discussed in context of approach A.

FIG. 3.

Structures discussed in context of approach B, incorporating the radioisotope chelator as the linker between targeting vector and fluorophore.

FIG. 4.

Structures discussed in context of approach C, incorporating the fluorophore as a linker between targeting vector and radioisotope.