Time-based position estimation in monolithic scintillator detectors.

Area of Science:

• Medical Physics
• Nuclear Instrumentation
• Medical Imaging

Background:

• Monolithic scintillation crystals coupled to pixelated photodetectors are used in medical imaging.
• Current detectors use light intensity for position and timing for interaction time.
• The spatio-temporal distribution of scintillation photons is underexplored for position estimation.

Purpose of the Study:

• To investigate the use of scintillation photon arrival times for gamma interaction position estimation.
• To develop a model for spatial resolution based exclusively on first photon timing.
• To evaluate the impact of detector parameters on timing-based position estimation.

Main Methods:

• Developed a model to predict spatial resolution using the time stamps of the first detected photons.
• Experimentally validated the model using a 16x16x10 mm LSO:Ce,0.2%Ca crystal.
• Coupled the crystal to a digital photon counter (DPC) array for data acquisition.

Main Results:

• The spatio-temporal distribution of photon arrival times provides information for position estimation.
• A spatial resolution of 3 mm (root mean squared error) was achieved using only timing data.
• The model showed good agreement with experimental measurements.

Conclusions:

• Scintillation photon timing is a viable method for estimating gamma interaction positions in detectors.
• This timing-based approach can complement or potentially replace intensity-based methods for improved spatial resolution.
• Detector parameters like scintillator properties and photodetector resolution significantly influence performance.