mTOR inhibitors are recently important tools for cancer treatment. They act on cell growth regulation, proliferation, and survival. Pharmacological therapy with mTOR inhibitors such as everolimus is emerging as an alternate approach. Meanwhile, early diagnosis is a hot target in cancer research. Conversely, it can be a novel diagnosis approach to monitor mTOR inhibitors during their pathway. From this point of view, radiolabeling of everolimus and its nanoformulation (EVE-PLGA nanoparticles) in high yields (95%) with an important diagnostic radionuclide (technetium-99m) is described. Besides, in vitro incorporation assays of radiolabeled everolimus and its nanoformulation against the cervix and ovarian cancer cells were demonstrated 8- and 12-times high values than control group. In conclusion, radiolabeled everolimus and its nanoformulation have a promise to improve on monitoring mTOR inhibitors.