28135
In order to develop new iodinated and fluorinated matched - pair radiotracers for Single - Photon Emission Computed Tomography ( SPECT ) / Positron Emission Tomography ( PET ) imaging and targeted radionuclide therapy of melanoma , we successfully synthesized and radiolabelled with iodine - 125 seven new derivatives , starting from our previously described lead structure 3 .
 Chemical: iodine - 125
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Answer:
 Chemical: iodine - 125