Highlights
- 60-minute dynamic 4D PET acquisition with ⁶⁸Ga-FAPI
- Time-resolved whole-body imaging in a U87MG tumor model
- 15 temporal frames with frame durations down to 2 minutes
- Early and late tracer distribution captured within a single imaging session
Introduction
Dynamic PET imaging enables time-resolved visualization of radiotracer distribution following administration, providing information that cannot be obtained from a single static acquisition.
In this study, ⁶⁸Ga-FAPI was evaluated in a U87MG tumor model using a continuous 60-minute dynamic PET acquisition.
Dynamic imaging protocol
A total activity of 9 MBq ⁶⁸Ga-FAPI was administered, followed by dynamic PET imaging from 0 to 60 min post injection.
The acquisition was reconstructed into 15 temporal frames, using shorter frames during the initial phase of tracer distribution:
- 0–10 min: 2-minute frames
- 10–60 min: 5-minute frames
This framing strategy provides higher temporal resolution during the early post-injection period while maintaining continuous coverage throughout the full 60-minute acquisition.
Dynamic PET visualization
The dynamic sequence enables visualization of the evolving whole-body distribution of ⁶⁸Ga-FAPI throughout the 60-minute acquisition.
During the first minutes post injection, prominent activity is observed in the kidneys and urinary bladder. Renal signal decreases rapidly over the following minutes, while tumor-associated uptake becomes progressively more distinct as background activity clears.
This time-resolved sequence captures both early tracer distribution and clearance, together with the progressive visualization of tumor uptake during the first hour post injection.
Figure 1: Dynamic 4D PET imaging of ⁶⁸Ga-FAPI in a U87MG tumor model. Injected activity: 9 MBq. Acquisition: 0–60 min post injection. Fifteen temporal frames with frame durations down to 2 min.
Conclusion
Dynamic ⁶⁸Ga-FAPI PET imaging provided continuous visualization of tracer distribution during the first hour post injection, capturing rapid changes in renal activity together with the progressive emergence of distinct tumor-associated uptake.
Short temporal frames during the early phase enable closer assessment of tracer kinetics and clearance while maintaining continuous whole-body imaging throughout the acquisition.