1 Department of Neuroimaging and Interventional Radiology (NI & IR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bangalore 560 029, India.
Background
Glucose is the renowned source of the energy for the cancer growth but amino acids (AAs) are also important fuel for the rapid proliferation of the cancer cells. Therefore, fluorine-18 [18F] and carbon-11 [11C] based AAs are widely in use due to inherit limitations of 1[18F]FDG for neuro-disorders application.
Aims
To prove radio synthesis challenges of 11C and 18F-labeled amino acid radiotracers in the FX2C/N tracerlab and their validation through PET-MR imaging.
Methods
We have used FX2C and FX2N Tracerlab modules for the synthesis of the [11C]methionine, [18F]choline and [18F]dopa. [18F]dopa was synthesized via Nucleophilic pathway in FX2N module. 11C-methionine was standardized in FX2C module using two different precursors. [18F]choline was synthesized using dimethylaminoethanol precursor and purified using cartridge-based method.
Results and Conclusion
The radiochemical purity of D-[11C], and L-[11C]methionine were 4.6 ± 3.2 % and 95.4 ± 3.6% . [18F]fluoromethylcholine was prepared with high radiochemical yield of 97.3 ± 2.6 % with yield of 8 ± 3%. L-[18F]-dopa was synthesized with high radiochemical yield of 95.8 ± 1.4% with 15 ± 3% yield. The adaptation of [18F]dopa synthesis to FX2N module via designing synthesis sequence and purified through on-line HPLC has provided high radiochemical purity. PET-MR imaging using these tracers have validated the synthesis and their availability for future clinical applications.
References
1. Chaturvedi, S., & Mishra, A. K. (2016). Small molecule radiopharmaceuticals - A review of current approaches. Frontiers in Medicine.
2. Guideline, I. H. T. (2005). ICH Q3C(R6) Impurities: Guideline for residual solvents Q3C (R5). Current Step.
3. Ha, N. S., Sadeghi, S., & van Dam, R. M. (2017). Recent progress toward microfluidic quality control testing of radiopharmaceuticals. Micromachines.