Endocrine Abstracts

Introduction and aim: MTC accounts for 5–10% of all thyroid cancers. Because of elevation postoperative calcitonin, short doubling time of calcitonin and no disease in available imaging techniques in some MTC patients, searching for new targets for radioisotope diagnostics is necessary.

Among other overexpression of GLP-1 receptors have been shown on parafollicular thyroid C-cells.

The aim of this study was to present the first experiences with the use of 99mTc-labeled GLP-1 analogue in MTC imaging.

Material and method: 99mTc-GLP-1 receptor scintigraphy with [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 was performed in 3 patients: man 70y, dissemination of MTC (2008), qualified to PRRT, local recurrence of MTC (2011); man 74y, metastatic lesions of MTC in liver and lymph nodes (2009), qualified to PRRT, since then stabilization of disease; man 22y, with genetically confirmed MEN2a syndrome, suspicion of local recurrence after abnormal pentagastric test (2009), USG revealed hypogenic leasion with following negative biopsy result. The lyophilized kit prepared by IAE POLATOM was used for preparing the tracer. WB scans were performed at 6 time points and SPECT at 3 points. The hybrid device SPECT/CT was used for performing examinations.

Results: In the first patient, 99mTc-GLP-1 scintigraphy confirmed the recurrence of the disease. In the second patient, a pathological tracer accumulation in the liver was found. For both patients the similar images to GLP-1 scintigraphy were obtained in SRS scintigraphy. In the third patient, the GLP-1 scintigraphy showed the tracer uptake in the same place as 99mTc and 131I scans. Due to lack of other lesion localizations, the patient was qualified to surgery. In all patients no side effects after the tracer injection were observed.

Conclusion: [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 seems to be an promising new tracer for clinical practice in case of MTC patients, to assess recurrence and advancement of the disease especially when standard imaging techniques failed.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.