Comparison of PET imaging with ⁶⁴Cu-liposomes and ¹⁸F-FDG in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch model of oral dysplasia and squamous cell carcinoma

Purpose: Currently, 2-deoxy-2-[¹⁸F]fluoro-d-glucose ( ¹⁸F-FDG) is the gold standard radiotracer for staging of head and neck cancer; however, the low sensitivity of this tracer can impede detection of early lesions. ⁶⁴Cu-liposomes accumulate in various cancers and provide both a sensitive tracer and an indication of the biodistribution of nanotherapeutics. Here, the accumulation of ⁶⁴Cu-liposomes in early and established cancers is assessed and compared with ¹⁸F-FDG in a head and neck cancer model. Methods: Lesions ranging from mild dysplasia to squamous cell carcinoma were induced in a hamster model of head and neck cancer by topical application of 7,12-dimethylbenz[a]anthracene to the buccal pouch. The hamsters were imaged with micro-positron emission tomography using ¹⁸F-FDG and ⁶⁴Cu-liposomes. Results: At 24 h postinjection, ⁶⁴Cu-liposome accumulation exceeded the accumulation of ¹⁸F-FDG in every pathologic grade. The lesion-to-cheek pouch (background) ratio and lesion-to-brain ratio were also higher for ⁶⁴Cu-liposomes than for ¹⁸F-FDG. Conclusion: Imaging of a nanotracer such as ⁶⁴Cu-liposomes can improve the visualization of head and neck tumors. Accumulation of liposomal particles in head and neck tumors over various pathologic grades averaged 3.5 %ID/cc demonstrating the potential for liposomal therapy with targeted chemotherapeutic agents.