PET imaging of medullary thyroid carcinoma in MEN2A transgenic mice using 6-[18F]F- L-DOPA.

6-[¹⁸F]Fluoro-3,4-dihydroxy- L-phenylalanine (6-[¹⁸F]F- L-DOPA) is increasingly used for PET imaging of neuroendocrine tumours. In this study, we investigated the use of 6-[¹⁸F]F- L-DOPA to detect and to monitor the progression of medullary thyroid carcinoma (MTC) in a genetically engineered mouse model of multiple endocrine neoplasia type 2A (MEN2A). Dynamic [¹⁸F]FDG and 6-[¹⁸F]F- L-DOPA small animal PET scans were acquired during 60 or 90 min in 8- to 20-month-old MEN2A transgenic mice. The kinetics of 6-[¹⁸F]F- L-DOPA, standardized uptake values (SUV) at 60 min and tumour volumes were recorded. The detection of MTCs using PET was confirmed by autopsy and histological analysis. 6-[¹⁸F]F- L-DOPA performs better than [¹⁸F]FDG for MTC detection in this transgenic mouse model. Uptake kinetics of 6-[¹⁸F]F- L-DOPA in MTCs are very different between mice but, in all cases, high contrast could be observed. Furthermore, 6-[¹⁸F]F- L-DOPA can detect tumours with sizes (1.8 mm³) that are near the resolution limit of PET, whereas they were undetectable by autopsy at the macroscopic level. 6-[¹⁸F]F- L-DOPA PET imaging can monitor the progression of MTCs in a genetically engineered mouse model. [ABSTRACT FROM AUTHOR]