The anilinoquinazoline derivative FEQA radiolabeled with the positron-emitting radioisotope fluorine F 18 with epidermal growth factor receptor (EGFR) binding and radioisotopic activities. Fluorine F 18 FEQA irreversibly binds to (EGFR), allowing imaging of EGFR-positive tumor cells with positron emission tomography (PET). or A radioactive substance being studied in positron emission tomography (PET) imaging to detect cancer and to monitor the response of some types of cancer to treatment. Fluorine F 18 FEQA attaches to the epidermal growth factor receptor (EGFR) found on the surface of some tumor cells. It is a type of radiopharmaceutical.