SU-E-CAMPUS-J-01: Monitoring of 19F-Labeled Immune Cell Trafficking During Radiotherapy Using MRI

Abstract

Purpose: Given the cross talk between cancer and the host immune system, there is a compelling need to monitor immunogenic responses in vivo during radiotherapy treatment. Over the last year our laboratory has been working toward (1) developing the nonradioactive isotope fluorine‐19 (19F), as a novel, clinically applicable tracking agent for immune cells using magnetic resonance imaging (MRI), and (2.) investigating if local irradiation of tumors augments expression of danger signals that recruit and activates immune cells using 19F MRI. Methods: Using a high‐resolution Varian 4.7 Tesla small animal MRI scanner several we have developed several imaging protocols to optimize a 19F MR imaging system that uses either a dedicated surface or volumetric fluorine coil. Given these protocols, human natural killer (NK) cells labeled with 19F‐PFPE were injected subcutaneously in the footpad of a mouse and scanned ∼1, 24, 48, 72, 120 hours after injection. Results: Initial experiments have demonstrated excellent SNR uniformity provided by the volume coil. Excellent signal linearity was demonstrated by acquiring images of phantom vials with increasing concentrations of 19F‐PFPE. We have also demonstrated the ability to monitor NK cells trafficking throughout the lymphatic system of a mouse. Conclusion: We are currently investigating the immunogenic response following irradiation of subcutaneous tumors in mice. The ability to monitor immune cell trafficking during therapy will help optimize the synergistic effects of radiation cytotoxicity and the host immune system. UW Carbone Cancer Center Pilot Grant