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3-O-Methyl-6-[[sup 18]F]fluoro-l-DOPA (OMFD) is a major metabolite of 6-[[sup 18]F]fluoro-L-DOPA. Although synthesis of OFMD was primarily established to study the dopaminergic system, as it is an amino acid analogue, uptake in experimental tumours has been found. The aim of this study was to evaluate the applicability of OMFD for brain tumour imaging and to obtain initial estimates of whole-body biodistribution and radiation dosimetry in humans. Nineteen patients with suspected or confirmed brain tumours were investigated with OMFD and dynamic brain PET, complemented by whole-body PET in seven patients. Tracer kinetics were compared for normal brain and intracerebral lesions. Tissue accumulation was quantified with standardised uptake values (SUVs). Whole-body distribution in combination with tracer kinetics from animal experiments was used for the calculation of radiation dosimetry data. On the basis of OMFD PET, viable brain tumour was suspected in 16 patients with SUVs of 3.0±0.8 and a tumour to non-tumour ratio of 1.9±0.5. Highest tumour and normal brain uptake occurred between 15 and 30 min, with a subsequent slow decrease. Late whole-body tracer distribution was uniform without specific organ accumulation. Elimination occurred via urine. The mean radiation dose to the whole body was estimated at 0.016 mSv/MBq, with the kidneys as dose-critical organ (0.033 mGy/MBq). In conclusion, OMFD enables the visualisation of brain tumours with SUVs similar to other fluorinated amino acids. The whole-body radiation exposure from OMFD is comparable to that from FDG imaging. [ABSTRACT FROM AUTHOR]

The 18F-labelled amino acid derivative 3-O-methyl-6-[18F]fluoro-l-DOPA ([18F]OMFD) is a potential radiotracer for imaging tumour tissue using positron emission tomography. The precursor N-formyl-3-O-methyl-4-O-boc-6-trimethyl-stannyl-l-DOPA-ethyl ester enables direct electrophilic radiofluorination by stereoselective destannylation. After partial hydrolysis, optimized HPLC purification and sterile filtration, the [18F]OMFD obtained with high radiochemical purity and ready for use. The total synthesis time is about 50 min and the radiochemical yield achieved is 20–25% (decay corrected, related to [18F]F2). It was demonstrated that [18F]OMFD could be produced routinely and reliably for clinical use. [18F]FDOPA-preparation devices can be used with minor modifications. [Copyright &y& Elsevier]