RT Journal Article SR Electronic T1 18F-Dihydroxyphenylalanine PET in Patients with Biochemical Evidence of Medullary Thyroid Cancer: Relation to Tumor Differentiation JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 524 OP 531 DO 10.2967/jnumed.107.047720 VO 49 IS 4 A1 Klaas P. Koopmans A1 Jan Willem B. de Groot A1 John T.M. Plukker A1 Elisabeth G.E. de Vries A1 Ido P. Kema A1 Wim J. Sluiter A1 Pieter L. Jager A1 Thera P. Links YR 2008 UL http://jnm.snmjournals.org/content/49/4/524.abstract AB Curative treatment for recurrent medullary thyroid cancer (MTC), diagnosed by rising serum calcitonin, is surgery, but tumor localization is difficult. Therefore, the value of 18F-dihydroxyphenylanaline PET (18F-DOPA PET), 18F-FDG PET, 99mTc-V-di-mercaptosulfuricacid (DMSA-V) scintigraphy, and MRI or CT was studied. Methods: Twenty-one patients with biochemical recurrent or residual MTC underwent 18F-DOPA PET, 18F-FDG PET, DMSA-V scintigraphy, and MRI or CT. Patient- and lesion-based sensitivities were calculated using a composite reference consisting of all imaging modalities. Results: In 76% of all patients with MTC, one or more imaging modalities was positive for MTC lesions. In 6 of 8 patients with a calcitonin level of <500 ng/L, imaging results were negative. In 15 patients with positive imaging results, 18F-DOPA PET detected 13 (sensitivity, 62%; with 4.6 lesions per patient [lpp]). Morphologic imaging (n = 19) was positive in 7 (sensitivity, 37%; 4.7 lpp), DMSA-V (n = 18) in 5 (sensitivity, 28%; 1.1 lpp), and 18F-FDG PET (n = 17) in 4 (sensitivity, 24%; 1.6 lpp). In a lesion-based analysis, 18F-DOPA PET detected 95 of 134 lesions (sensitivity, 71%), morphologic imaging detected 80 of 126 (sensitivity, 64%), DMSA-V detected 20 of 108 (sensitivity, 19%), and 18F-FDG PET detected 48 of 102 (sensitivity, 30%). In 2 of 3 patients with a calcitonin/carcinoembryonic antigen (CEA) doubling time of ≤12 mo, 18F-FDG PET performed better than 18FDOPA PET; in the third patient, 18F-FDG PET was not performed. Conclusion: MTC lesions are best detectable when serum calcitonin was >500 ng/L. 18F-DOPA PET is superior to 18F-FDG PET, DMSA-V, and morphologic imaging. With short calcitonin doubling times (≤12 mo), 18F-FDG PET may be superior.