Evaluation of positron emission tomography as a method to visualize subsurface microbial processes.

Area of Science:

• Environmental Microbiology
• Geochemistry
• Nuclear Imaging

Background:

• Positron emission tomography (PET) offers high sensitivity and resolution for spatiotemporal monitoring.
• PET has not been previously applied to image in situ soil microbial processes.
• Subsurface bacteria play crucial roles in geochemical cycles and contaminant remediation.

Purpose of the Study:

• To evaluate the feasibility of using PET imaging to monitor subsurface bacterial activity in soil.
• To demonstrate the application of PET for visualizing radiotracer-labeled bacteria in situ.
• To assess PET's potential for studying subsurface microbiology and geochemistry.

Main Methods:

• Soil columns were packed with simulated mineral soils.
• Columns were inoculated with radiotracer-labeled Rahnella sp. Y9602 bacteria.
• 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)FDG) was used to label metabolically active bacteria.
• [(18)F]fluoride ion was used to measure hydraulic conductivity.

Main Results:

• PET imaging successfully visualized the distribution of (18)FDG-labeled Rahnella sp. Y9602 in soil columns.
• The study confirmed the applicability of (18)FDG as a tracer for metabolically active subsurface bacteria.
• [(18)F]fluoride ion proved effective for measuring hydraulic conductivity in the soil columns.

Conclusions:

• PET imaging is a viable non-destructive technique for monitoring subsurface bacterial activity.
• Positron-emitting isotopes can be utilized to elucidate subsurface microbiology and geochemical processes.
• This approach holds significant potential for contaminant remediation research.