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

PURPOSE: 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). METHODS: 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. RESULTS: 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. CONCLUSION: 6-[(18)F]F-L-DOPA PET imaging can monitor the progression of MTCs in a genetically engineered mouse model.

Easy upgrade of the TRACERLab FX C Pro for [¹¹C]carboxylation reactions: application to the routine production of [1-¹¹C]acetate.

Carbon-11-labeled acetate ([1-(11)C]acetate) is a radiopharmaceutical of importance in clinical practice as well as in preclinical research in cardiology and oncology. Its preparation is based on the [(11)C]carboxylation reaction of a Grignard reagent with [(11)C]CO2. Most of the commercially available synthesizers are only dedicated to the preparation of [(11)C]methyl iodide (or [(11)C]methyl triflate) for the radiomethylation of an appropriate precursor but not for the direct use of cyclotron-produced [(11)C]CO2. Based on the classical [(11)C]carboxylation reaction and SPE purification, we propose in this technical note a detailed, simple, easy-to-handle and fully reversible modification of the TRACERLab FX C Pro to operate, on demand, [(11)C]carboxylation reactions, exemplified herein by the production of [1-(11)C]acetate, or [(11)C]radiomethylation reactions. This also opens new prospects to other type of radiochemical reactions involving [(11)C]CO2.

[18F]DPA-714, [18F]PBR111 and [18F]FEDAA1106-selective radioligands for imaging TSPO 18 kDa with PET: automated radiosynthesis on a TRACERLAb FX-FN synthesizer and quality controls.

Imaging of TSPO 18 kDa with PET is more and more considered as a relevant biomarker of inflammation in numerous diseases. Development of new radiotracers for TSPO 18 kDa has seen acceleration in the last years and the challenge today is to make available large amounts of such a radiotracer in compliance with GMP standards for application in humans. We present in this technical note automated productions of [(18)F]DPA-714, [(18)F]PBR111 and [(18)F]FEDAA1106, three promising radiotracers for TSPO 18 kDa imaging, using a TRACERlab FX-FN synthesizer. This note also includes the quality control data of the validation batches for the manufacturing qualification of clinical production of [(18)F]DPA-714.