Optimization of time frame binning for FDOPA uptake quantification in glioma

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Oncology

Background:

• Quantification of 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (FDOPA) uptake in glioma assessment using dynamic PET can be inaccurate due to non-optimal time-activity curve (TAC) binning.
• Under- or over-sampling dynamic PET images significantly affects kinetic parameter quantification.

Purpose of the Study:

• To optimize the temporal time frame binning for dynamic FDOPA PET imaging in glioma assessment.
• To identify a sampling strategy that minimizes bias in kinetic parameter quantification.

Main Methods:

• Analyzed 33 tumoral TACs from 14 patients with biopsy-proven gliomas.
• Compared mean SUVmax tumor-to-brain ratios (TBRmax) at 20 min and 35 min post-injection (p.i).
• Evaluated five different time frame sampling strategies using simulated noisy TACs and Monte Carlo methods, comparing extracted K1 values to a target K1 value.

Main Results:

• Mean TBRmax was significantly higher at 20 min p.i. compared to 35 min p.i. (1.4 ± 0.8 vs. 1.2 ± 0.6; p <0.001).
• The optimal time frame binning was identified as 8x15sec-2x30sec-2x60sec-3x300sec.
• K1 values from the optimal binning were significantly different from most other tested samplings, except for 11x10sec-6x15sec-5x20sec-3x300sec.

Conclusions:

• The proposed optimal sampling schedule (8x15sec-2x30sec-2x60sec-3x300sec) can minimize bias in FDOPA uptake quantification for glioma assessment using kinetic analysis.
• This optimized binning strategy enhances the reliability of dynamic FDOPA PET imaging in clinical practice.