[¹⁸F]FDOPA positron emission tomography in manganese-exposed workers

Area of Science:

• Neuroscience
• Occupational Health
• Radiology

Background:

• Occupational manganese (Mn) exposure is a known risk factor for parkinsonism.
• The precise mechanisms underlying Mn neurotoxicity remain unclear.
• Positron emission tomography (PET) imaging offers a non-invasive method to evaluate dopaminergic neuronal function.

Purpose of the Study:

• To investigate the relationship between occupational Mn exposure from welding and FDOPA PET uptake in the striatum.
• To assess the association between Mn exposure, striatal FDOPA uptake, and clinical parkinsonism (UPDRS3 scores).

Main Methods:

• Acquired FDOPA PET scans from 72 subjects: 27 Mn-exposed welders, 14 other Mn-exposed workers, and 31 non-exposed controls.
• Estimated cumulative welding exposure using detailed work histories.
• Utilized linear regression, adjusting for age, to analyze the association between welding exposure and FDOPA uptake in the caudate and putamen.

Main Results:

• Mn-exposed welders and other Mn-exposed workers showed significantly lower mean caudate FDOPA uptake compared to non-exposed subjects (p≤0.001).
• No clear dose-response relationship was observed between caudate FDOPA uptake and the level of Mn exposure or UPDRS3 scores.
• FDOPA PET indicated pre-synaptic dopaminergic dysfunction in Mn-exposed individuals.

Conclusions:

• Occupational manganese exposure, particularly from welding, is associated with pre-synaptic dopaminergic dysfunction in the striatum.
• This dopaminergic dysfunction, as detected by FDOPA PET, was not directly correlated with the severity of clinical parkinsonism symptoms in the studied population.