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A Protocol for Real-time 3D Single Particle Tracking
Published on: January 3, 2018
An Accurate Timing Alignment Method with Time-to-Digital Converter Linearity Calibration for High-Resolution TOF PET
Hongdi Li1, Chao Wang1, Shaohui An1
1H. Baghaei, Y. Zhang, R. Ramirez and W.-H. Wong are with The University of Texas MD Anderson Cancer Center, Houston, Texas, USA. H. Li, S. An, C. Wang and S. Liu were with The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; they are now with UIH, Shanghai, China. X. Lu and Y. Dong are with UIH, Shanghai, China.
Accurate timing alignment in positron emission tomography (PET) systems is crucial for reducing random events and enhancing image quality. This study presents a novel method using a phantom to achieve timing alignment accuracy better than ±25 ps for time-of-flight PET imaging.
Area of Science:
- Medical Imaging
- Nuclear Medicine
- Instrumentation
Background:
- Accurate timing alignment in Positron Emission Tomography (PET) systems is essential for minimizing coincidence time windows.
- This reduction in time window is critical for decreasing random events and improving overall image quality.
- Precise timing is also a fundamental requirement for advanced time-of-flight (TOF) image reconstruction techniques.
Purpose of the Study:
- To develop and validate a novel method for precise timing alignment of a TOF PET system.
- To assess the achievable timing alignment accuracy and its impact on system performance.
- To establish a robust calibration procedure for TOF PET detectors.
Main Methods:
- Utilized a thin annular cylinder (shell) phantom filled with a radioactive source, positioned centrally within the PET camera.
- Measured time differences between coincidence detector pairs.
- Calibrated time-to-digital converter (TDC) nonlinearity and derived intrinsic time biases for each detector using an iterative algorithm.
- Implemented raw time bias correction in front-end electronics and residual fine bias during TOF list-mode reconstruction.
Main Results:
- Achieved a timing alignment accuracy of better than ±25 picoseconds (ps).
- Measured a preliminary timing resolution of 473 ps (full width at half maximum) on a prototype TOF PET/CT system.
- Demonstrated the effectiveness of the iterative algorithm in deriving intrinsic time biases.
Conclusions:
- The developed phantom-based method provides highly accurate timing alignment for TOF PET systems.
- This method significantly improves PET imaging by reducing random events and enhancing image quality.
- The achieved accuracy and resolution pave the way for more precise quantitative imaging in TOF PET/CT.
