Diagnosis of Melanoma with 61 Cu-Labeled PET Tracer.

Until the recent years, substances containing radioactive ⁶¹ Cu were strongly considered as potential positron-emitting radiopharmaceuticals for use in positron emission tomography (PET) applications; however, due to their suitably long half-life, and generator-independent and cost-effective production, they seem to be economically viable for human imaging. Since malignant melanoma (MM) is a major public health problem, its early diagnosis is a crucial contributor to long-term survival, which can be achieved using radiolabeled α-melanocyte-stimulating hormone analog NAPamide derivatives. Here, we report on the physicochemical features of a new CB-15aneN ₅ -based Cu(II) complex ([Cu(KFTGdiac)] ^- ) and the ex vivo and in vivo characterization of its NAPamide conjugate. The rigid chelate possesses prompt complex formation and suitable inertness ( t _1/2 = 18.4 min in 5.0 M HCl at 50 °C), as well as excellent features in the diagnosis of B16-F10 melanoma tumors (T/M(SUVs) ( in vivo ): 12.7, %ID/g: 6.6 ± 0.3, T/M ( ex vivo ): 22).