Radiochemistry for a beta tomorrow: The application of radiochemistry toward molecular imaging and therapy of cancer

   Radiochemistry takes advantage of the useful properties of radioactive materials to further the investigation of chemical behavior and phenomena. This can be done on a range of scales from examining a specific reaction to tracking a chemical’s interaction with complex environments including biological systems.

   One focus of the Returning the Radio to Chemistry IGERT is investigating ligand design for nonstandard radionuclides for use in molecular imaging and radioimmunotherapy of cancer. Two such projects involve synthesizing and evaluating bifunctional chelators for Zirconium-89 for Positron Emission Tomography (PET) imaging and Rhenium-188 for radiotherapy.

   Zirconium-89 has been found to be an ideal radionuclide for PET imaging with antibodies due to the fact that its half-life is well matched to antibody circulation time in the body and allows for imaging after the antibody-radiometal tracer has localized in a tumor. The design, synthesis, and evaluation of novel octadentate bifunctional chelates for the conjugation of Zr-89 to IgG antibodies is currently underway in order to create a more stable complex and reduce the amount of Zr-89 released in vivo.

   Conversely, rhenium-188 can be conjugated to an antibody as a possible Single Photon Emission Computed Tomography (SPECT) imaging agent, but in addition its high energy beta decay makes it useful for targeted radiotherapy. In exploring various ligands to bind Re-188, it has been found that the behavior of the complexes varies greatly between the tracer and macroscopic levels.