A count-rate model for PET scanners using pixelated Anger-logic detectors with different scintillators

Area of Science:

• Medical Physics
• Nuclear Medicine
• Instrumentation

Background:

• High count-rate performance is crucial for Positron Emission Tomography (PET) scanners.
• Understanding scintillator properties' impact on scanner deadtime and pulse pileup is essential.

Purpose of the Study:

• To apply a high count-rate simulation (HCRSim) model to PET scanners with pixelated Anger-logic detectors.
• To investigate the influence of scintillator stopping power, decay time, and energy resolution on scanner performance at high activity levels.

Main Methods:

• Developed and utilized a high count-rate simulation (HCRSim) model based on fundamental physics principles.
• Simulated whole-body PET scanners (NEMA NU2-2001 standard) using lanthanum bromide (LaBr(3)), gadolinium orthosilicate (GSO), and lutetium orthosilicate (LSO) scintillators.
• Analyzed deadtime, pulse pileup, scatter fraction, sensitivity, and noise equivalent count (NEC) rate.

Main Results:

• Pixelated Anger-logic detectors show potential for high count-rate performance, correlating with NEC rate.
• LaBr(3) and LSO scanners exhibit reduced deadtime and randoms fraction compared to GSO due to faster signal decay and shorter coincidence timing windows.
• LaBr(3) offers the lowest scatter fraction and highest NEC at high activities, while LSO provides the highest sensitivity and peak NEC at lower activities.

Conclusions:

• Scintillator properties significantly impact PET scanner deadtime, pulse pileup, and NEC rate at high activities.
• LaBr(3) and LSO scintillators offer advantages over GSO for high count-rate PET imaging.
• The HCRSim model provides valuable insights for optimizing PET scanner design and performance.