Not only did pretargeted immunoscintigraphy correctly localize primary tumors and recurrences in medullary thyroid cancer patients, false-negatives (when the tumor does not express high level of CEA therefore not detectable by radiolabeled anti-CEA antibodies) could also potentially be avoided since this three-step strategy can significantly enhance the tumor contrast, thus allowing for accurate detection of lesions with low CEA expression level. Here, CEACAM5 is linked to neoplasm.