Imaging neuronal pathways with ⁵²Mn PET: Toxicity evaluation in rats

Area of Science:

• Neuroscience
• Radiochemistry
• Medical Imaging

Background:

• Manganese (Mn2+) traces neuronal pathways due to activity-dependent uptake and synaptic transport.
• Magnetic Resonance Imaging (MRI) uses Mn2+ as a contrast agent, but requires high doses due to limited sensitivity.
• High Mn2+ doses raise toxicity concerns, especially for long-term studies.

Purpose of the Study:

• To introduce manganese-52 (52Mn) as a novel tracer for Positron Emission Tomography (PET) imaging of neuronal tracts.
• To evaluate the efficacy and safety of 52Mn for visualizing specific neural pathways in vivo.

Main Methods:

• Administered 52Mn in rats via injection into the ventral tegmental area (VTA) and dorsal striatum (STR).
• Utilized PET imaging to visualize dopaminergic and striatonigral pathways.
• Assessed potential toxicity using behavioral tests and histological analysis of brain tissue.

Main Results:

• Neuronal tracts were clearly visualized using PET imaging 24 hours after 52Mn administration.
• High doses (150-170 kBq) of 52Mn caused behavioral impairment and DNA damage.
• Reduced doses (20-30 kBq) of 52Mn were sufficient for PET imaging and eliminated adverse effects.

Conclusions:

• 52Mn is a viable PET tracer for neuronal tract imaging.
• A low-dose (20-30 kBq) 52Mn protocol allows for effective and safe visualization of neural pathways.
• This approach overcomes the toxicity limitations associated with high-dose Mn2+ for MRI.