Explicit measurement of multi-tracer arterial input function for PET imaging using blood sampling spectroscopy

Area of Science:

• Nuclear medicine
• Medical imaging
• Biomedical engineering

Background:

• Conventional positron emission tomography (PET) is typically limited to one tracer per scan.
• A new multi-tracer PET technique is proposed, utilizing dynamic imaging and compartment modeling.
• This method requires at least one non-pure positron emitting tracer for accurate arterial input function (AIF) derivation via blood sampling spectroscopy.

Purpose of the Study:

• To validate a novel multi-tracer PET technique for simultaneous cardiac imaging.
• To assess the feasibility of obtaining separate quantitative information for co-injected tracers.
• To compare in vivo multi-tracer PET results with ex vivo tissue analysis.

Main Methods:

• In vivo cardiac PET/CT studies were performed on pigs using 18FDG and 68Ga-DOTA in a single acquisition.
• Arterial input functions (AIFs) for each tracer were derived from blood samples using spectroscopic analysis.
• A multi-tracer compartment model was applied to myocardial data, and results were compared with ex vivo tissue analysis.

Main Results:

• The multi-tracer PET technique demonstrated a high correlation with ex vivo analysis for both 18FDG relative activity (r = 0.95) and SUV (r = 0.98).
• Quantitative distribution and uptake of each tracer were successfully obtained.
• The method proved effective in differentiating signals from co-injected tracers.

Conclusions:

• The developed technique enables simultaneous PET scanning with two tracers.
• Separate quantitative information for each tracer can be obtained within a single acquisition.
• This advancement offers potential for more comprehensive and efficient PET imaging.