High-contrast PET of melanoma using F-18-MEL050, a selective probe for melanin with predominantly renal clearance

The aim of this study was to evaluate the novel probe 18F-6-fluoro-N-[2-(diethylamino)ethyl] pyridine-3-carboxamide (18F-MEL050) for the imaging of primary and metastatic melanoma. Methods: PET using 18F-MEL050 was performed in murine models of melanoma. The specificity of 18F-MEL050 was studied by comparing its accumulation in pigmented B16-F0 allograft tumors with that of human amelanotic A375 xenografts using PET and high-resolution autoradiography. 18F-MEL050 PET results were compared with 18F-FDG PET, the current standard in melanoma molecular imaging. To test the ability of 18F-MEL050 to assess the metastatic spread of melanoma, a murine model of lung metastasis was imaged by PET/CT, and results correlated with physical assessment of tumor burden in the lungs. Results: In pigmented B16-F0 grafts, 18F-MEL050 PET yielded a tumor-to-background ratio of approximately 20:1 at 1 h and greater than 50:1 at 2 and 3 h. In the B16-F0 melanoma allograft model, tumor-to-background ratio was more than 9-fold higher for 18F-MEL050 than for 18F-FDG (50.9 ± 6.9 vs. 5.8 ± 0.5). No uptake was observed in the amelanotic melanoma xenografts. Intense uptake of 18F-MEL050 was evident in metastatic lesions in the lungs of B16-BL6 tumor–bearing mice on PET at 2 h after tracer injection, with high concordance between 18F-MEL050 accumulation on PET/CT and tumor burden determined at necroscopy. Conclusion: 18F-MEL050 has a rapid tumor uptake and high retention with specificity for melanin, suggesting great potential for noninvasive clinical evaluation of suspected metastatic melanoma. © 2010, Society of Nuclear Medicine

Keywords

Neoplasms, Melanin, Renal clearance, Positron computed tomography, Lungs, Mice

Citation

Denoyer, D., Greguric, I., Roselt, P., Neels, O. C., Aide, N., Taylor, S. R., Katsifis, A., Dorow, D. S., & Hicks, R. J. (2010). High-contrast PET of melanoma using F-18-MEL050, a selective probe for melanin with predominantly renal clearance. Journal of Nuclear Medicine, 51(3), 441-447. doi:10.2967/jnumed.109.070060