177Lu-PP-F11N for Receptor Targeted Therapy and Imaging of Metastatic Thyroid Cancer.

Inclusion Criteria: Phase 0 study * Advanced MTC with elevated levels of calcitonin (\> 100 pg/ml) and/or calcitonin-doubling time \< 24 months before or after total thyroidectomy or * Patients with well differentiated GEP-NET (grade 1-3) with a Ki67 index of up to 55% or NET of the lung or thymus (grade 1 and 2) with low or missing expression of SST2-receptor and progressive disease within the last 6 months according to RECIST 1.1 * Age \> 18 years * Informed consent Phase I study * Diagnostic, contrast medium enhanced CT scan neck/thorax/abdomen, not older than 4 weeks * Advanced MTC with elevated levels of calcitonin (\> 100 pg/ml) and/or calcitonin-doubling time \< 24 months before or after total thyroidectomy- Age \> 18 Years * Informed consent * Curative surgical therapy not possible Exclusion Criteria: Phase 0 study * Medication with Vandetanib 3 weeks before the study and during the study * Renal failure (calculated glomerular filtration rate (GFR) \< 60 ml/min per 1.73 m2 body surface). * Bone marrow failure (thrombocytes \< 70 000/μl, leucocytes \< 2 500/μl, hemoglobin \< 8 g/dl). * Pregnancy and breast feeding * Knows allergic reaction on Physiogel or other gelatine products * Known, serious side reaction in the case of a former application of pentagastrin * Active, second malignancy oder remission after second malignancy \< 5 years Phase I study * Medication with Vandetanib 3 weeks before the study and during the study * Renal failure (calculated GFR \< 50 ml/min per 1.73 m2 body surface). * Bone marrow failure (thrombocytes \< 100 000/μl, leucocytes \< 3 000/μl, hemoglobin \< 10 g/dl). * Pregnancy and breast feeding * Known, serious side reaction in the case of a former application of pentagastrin * Active, second malignancy oder remission after second malignancy \< 5 years