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

Abstract

6-[(18)F]Fluoro-3,4-dihydroxy-L-phenylalanine (6-[(18)F]F-L-DOPA) is increasingly used for PET imaging of neuroendocrine tumours. In this study, we investigated the use of 6-[(18)F]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 [(18)F]FDG and 6-[(18)F]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-[(18)F]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-[(18)F]F-L-DOPA performs better than [(18)F]FDG for MTC detection in this transgenic mouse model. Uptake kinetics of 6-[(18)F]F-L-DOPA in MTCs are very different between mice but, in all cases, high contrast could be observed. Furthermore, 6-[(18)F]F-L-DOPA can detect tumours with sizes (1.8 mm(3)) that are near the resolution limit of PET, whereas they were undetectable by autopsy at the macroscopic level. 6-[(18)F]F-L-DOPA PET imaging can monitor the progression of MTCs in a genetically engineered mouse model.