PT - JOURNAL ARTICLE AU - Fröberg, Alida AU - Nock, Berthold AU - Maina, Thea AU - De Jong, Marion AU - De Herder, Wouter AU - Van Eijck, Casper AU - Smits, Marion AU - Hijmans, Caroline AU - Breeman, Wouter AU - Krenning, Eric TI - <sup>99m</sup>Tc-Demogastrin 2 for CCK-2 receptor scintigraphy in medullary thyroid carcinoma DP - 2010 May 01 TA - Journal of Nuclear Medicine PG - 402--402 VI - 51 IP - supplement 2 4099 - http://jnm.snmjournals.org/content/51/supplement_2/402.short 4100 - http://jnm.snmjournals.org/content/51/supplement_2/402.full SO - J Nucl Med2010 May 01; 51 AB - 402 Objectives In medullary thyroid carcinoma (MTC) serum calcitonin is a very sensitive and specific tumor marker. However, localization of recurrent tumor or metastases is often not possible with presently available diagnostic imaging modalities. MTC often (&gt;90%) overexpresses cholecystokin-2 receptors (CCK2R), these might be viable targets for radionuclide scintigraphy. Results of 99mTc-N4-Gly-(D)Glu-(Glu)5-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 (99mTc-Demogastrin 2) scintigraphy in patients (pts) with primary MTC (preoperatively) and pts with elevated serum calcitonin levels after neck surgery are reported. Methods 32 pts (21 female; age 17-76 y, median 43 y) were studied, 3 preoperative. 17 pts had elevated calcitonin levels but no known tumor localization. Scintigraphy was performed at 3-4 and/or 8 and/or 24 h post injection of ± 800 MBq 99mTc-Demogastrin 2. Results 15 pts had known tumor localizations; with exception of a pt with only small liver metastases (3 mm which scan equivocal), the radionuclide scan of all these pts was judged positive. In 8 of them additional lesions were found. Of 17 pts without known tumor lesions 9 pts had positive lesions in neck, mediastinum/lung-hilum, bone, lung and/or liver. In 7 of these 9 pts at least 1 lesion was confirmed with CT, MRI and/or ultrasound. The smallest positive neck lesion was 2.9 mm (cytology showed MTC). In 2 pts lesions have not yet been confirmed. In 2 pts non-visualized neck lesions were subsequently discovered by other means and resected; in-vitro autoradiography of these metastases showed lack of clear CCK2R overexpression. Conclusions Total body CCK2R imaging with 99mTc-Demogastrin 2 can be helpful to localize MTC metastases as even very small metastases (&lt; 5 mm) and lesions at unexpected locations could be visualized. Further studies are needed to define its value in patient management