Molecular imaging of lymphoid organs and immune activation using positron emission tomography with a new 18F-labeled 2′-deoxycytidine analog


Monitoring immune function using molecular imaging could significantly impact the diagnosis and treatment evaluation of immunological disorders and therapeutic immune responses. Positron Emission Tomography (PET) is a molecular imaging modality with applications in cancer and other diseases. PET studies of immune function have been limited by a lack of specialized probes. We identified [18F]FAC (1-(2′-deoxy-2′-[18F]fluoroarabinofuranosyl) cytosine) by differential screening as a new PET probe for the deoxyribonucleotide salvage pathway. [18F]FAC enabled visualization of lymphoid organs and was sensitive to localized immune activation in a mouse model of anti-tumor immunity. [18F]FAC microPET also detected early changes in lymphoid mass in systemic autoimmunity and allowed evaluation of immunosuppressive therapy. These data support the use of [18F]FAC PET for immune monitoring and suggest a wide range of clinical applications in immune disorders and in certain types of cancer.

Nat Med. Author manuscript; available in PMC 2009 Aug 3.
Published in final edited form as:
Nat Med. 2008 Jul; 14(7): 783–788.
Published online 2008 Jun 8. doi: 10.1038/nm1724

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