High-performance electronics for time-of-flight PET systems.

Area of Science:

• Medical Imaging
• Nuclear Instrumentation
• Electronics Engineering

Background:

• Time-of-flight positron emission tomography (TOF PET) requires high-precision timing electronics for accurate event localization.
• Commercial PET camera electronics, like the Siemens/CPS Cardinal system, have limitations in timing resolution due to integrated circuit (IC) components.
• Key components limiting timing resolution are the constant fraction discriminator (CFD) and time-to-digital converter (TDC) within the ASIC.

Purpose of the Study:

• To design and build a high-performance readout electronics system for TOF PET cameras.
• To improve the timing resolution of TOF PET systems by addressing limitations in existing electronics.
• To validate the performance of the improved electronics in a custom TOF PET camera.

Main Methods:

• Modified the architecture of commercial PET camera electronics, specifically the Analog subsection board.
• Replaced the application-specific integrated circuit (ASIC) based CFD and TDC with discrete component CFD and a high-performance CERN TDC ASIC.
• Integrated the improved Analog subsection board into a custom single-ring LSO-based TOF PET camera.

Main Results:

• The upgraded electronics system achieved an overall timing resolution of 60 picoseconds (ps) Full Width at Half Maximum (FWHM).
• Prototype TOF detector modules coupled with Lutetium-based Oxyorthosilicate (LSO) crystals yielded a coincidence timing resolution of 259 ps FWHM.
• Detector modules using Lanthanum(III) Bromide (LaBr3) crystals achieved a coincidence timing resolution of 156 ps FWHM.

Conclusions:

• The developed readout electronics system significantly enhances timing resolution in TOF PET.
• Replacing integrated CFD and TDC with higher-performance discrete and ASIC components is crucial for improving TOF PET timing accuracy.
• The improved system demonstrates potential for advancing the performance of TOF PET imaging.