Characterization of dynamic 3-D PET imaging for functional brain mapping

Area of Science:

• Neuroimaging
• Medical Physics
• Radiochemistry

Background:

• Positron emission tomography (PET) is crucial for functional brain mapping.
• Optimizing PET acquisition, reconstruction, and analysis is vital for enhanced sensitivity.
• Existing methods require improvements in temporal resolution and image quality.

Purpose of the Study:

• To investigate methods for optimizing PET imaging for functional brain mapping.
• To compare 2-D and 3-D PET modes for signal-to-noise ratio and efficiency.
• To develop and implement faster reconstruction algorithms for dynamic 3-D PET studies.

Main Methods:

• Measured scatter fraction and noise-equivalent count rates for ECAT 951/31R scanner in 2-D and 3-D modes.
• Developed and implemented a parallelized 3-D reconstruction algorithm on a supercomputer.
• Conducted dynamic 3-D PET activation studies using H2(15)O infusions and a lexical decision task in 12 subjects.

Main Results:

• 3-D PET mode yielded higher signal-to-noise images than 2-D mode at specific activities < 30 kBq/ml.
• Parallelized reconstruction algorithm increased speed tenfold compared to single-processor systems.
• Detected significant regional cerebral blood flow (CBF) changes in all imaging phases (during, immediately after, and 1 min after stimulation).

Conclusions:

• Dynamic 3-D (4-D) PET scanning is practical for functional brain mapping.
• Optimized PET methods improve sensitivity for detecting subtle regional CBF changes.
• Advanced 3-D reconstruction and dynamic scanning enhance the utility of PET in neuroscience research.