In 2012, Fujinaga et al. developed three novel PET tracers, [11C]6, [18F]7 and [18F]8, demonstrating the effectiveness of [11C]6 for monitoring mGluR1 expression in the rodent brain.205 On the basis of the studies with multiple radioligands in brain imaging, the authors further reported the first imaging of mGluR1 in melanoma using [18F]7. The gene discussed is GRM1; the disease is melanoma.