Abstract
Background
Particle therapy depends on protons or heavier ions stopping at the intended depth in the patient. Verifying that range during or immediately after treatment is therefore an important part of treatment quality assurance.
Approach
This feasibility study investigates whether the digital tracking calorimeter developed by the Bergen pCT collaboration can perform range verification by measuring secondary charged particles. Monte Carlo simulations modeled proton and carbon-ion beams at medically relevant energies passing through water phantoms of different thicknesses. Regression models then predicted the beam range from the simulated detector readout.
Results
Carbon ions produced a higher detector readout yield and lower prediction errors despite the simulations using 100 times fewer primary carbon ions than protons. Kernel regression achieved the lowest mean absolute error for protons at 0.27 ± 0.04 mm. A Gaussian process achieved 0.18 ± 0.02 mm for carbon ions.
Significance
The results show that a digital tracking calorimeter can support in-situ range verification for both proton and carbon-ion therapy using secondary charged particles.
Key Contributions
- First feasibility study of secondary charged-particle range verification with the digital tracking calorimeter designed by the Bergen pCT collaboration
- Direct comparison of range-prediction precision for proton and carbon-ion therapy
- Submillimeter prediction errors for both treatment modalities in Monte Carlo simulations
Technologies & Methods
- GATE/Geant4 Monte Carlo simulation of particle transport and detector response
- Machine learning regression models for beam-range prediction
- Digital tracking calorimetry for secondary charged-particle detection
- Proton and carbon-ion therapy treatment scenarios