Calculating 1/β²p² for most likely path estimates for protons and helium ions using an analytical model

Area of Science:

• Medical Imaging
• Computational Physics
• Particle Therapy

Background:

• Ion computed tomography (CT) spatial resolution is limited by ion scattering.
• Accurate modeling of ion trajectories, like the most likely path (MLP), is crucial for image reconstruction.
• Current MLP implementations often rely on Monte Carlo simulations for scattering parameters.

Purpose of the Study:

• To develop and validate an analytical method for calculating the 1/β(w)²p(w)² term for MLP.
• To improve the accuracy of scattering matrices used in ion CT image reconstruction.
• To assess the performance of the analytical model for protons and helium ions in water targets.

Main Methods:

• Utilized an existing analytical model for ion ranges and stopping powers to compute 1/β(w)²p(w)².
• Calculated scattering matrices for the MLP using the analytical model.
• Investigated the model for protons and helium ions across various energies and water phantom depths.
• Compared analytical results with GATE Monte Carlo simulations.

Main Results:

• The analytical model accurately calculated 1/β(w)²p(w)² for protons and helium ions.
• The root-mean-square error between MLP estimates using calculated and simulated values was less than 3 μm.
• The model demonstrated consistent performance across different energies and phantom lengths.

Conclusions:

• An analytical approach can reliably compute scattering parameters for MLP in ion CT.
• This method offers a computationally efficient and accurate alternative to Monte Carlo simulations.
• The findings support the integration of this analytical model for enhanced spatial resolution in ion CT.