Analytical positron range modelling in heterogeneous media for PET Monte Carlo simulation

Area of Science:

• Medical Physics
• Computational Imaging
• Radiochemistry

Background:

• Monte Carlo (MC) simulations are accurate for positron interactions but computationally slow.
• Analytical models offer a faster alternative for positron range estimation.
• Simulating positron range in heterogeneous media presents a significant challenge.

Purpose of the Study:

• To efficiently implement and validate an analytical positron range model.
• To incorporate medium heterogeneity into the analytical model.
• To investigate the influence of positronium formation on positron range and simulation accuracy.

Main Methods:

• Developed and validated an analytical model for positron range using annihilation density distributions.
• Compared analytical model results with the GATE Monte Carlo simulator.
• Investigated positronium formation effects on positron range and simulation performance.

Main Results:

• 1D annihilation density distributions were accurately fitted with Gaussian functions and stored in look-up tables.
• The analytical model, including heterogeneity, enables efficient positron range modeling in MC simulations.
• The model showed good agreement with GATE for lower energy positron emitters like (18)F and (11)C.

Conclusions:

• The developed analytical model provides an efficient and accurate method for simulating positron range, particularly for lower energy emitters.
• The approach is suitable for integration into Monte Carlo simulations, enhancing computational efficiency.
• Further research is needed to draw reliable conclusions on the impact of positronium formation.