Integrated-mode proton radiography with 2D lateral projections

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Image Reconstruction

Background:

• Proton radiography generates water equivalent thickness (WET) maps for motion management and range verification in proton therapy.
• Current reconstruction methods using single cameras (distal or lateral range telescope) yield limited image quality.

Purpose of the Study:

• To introduce a novel reconstruction framework utilizing 2D information from two lateral view cameras.
• To enhance image quality in proton radiography compared to existing methods.

Main Methods:

• A new reconstruction framework employing two lateral view cameras was developed.
• Methods were compared using Geant4 Monte Carlo simulations with XCAT phantom and slanted edge phantoms.
• Experimental validation was performed using a plastic volumetric scintillator and various phantoms.

Main Results:

• The proposed method achieved a resolution of 0.33 lp mm⁻¹ on a simulated slanted edge phantom, an improvement over the distal method (0.24 lp mm⁻¹).
• Mean absolute error on WET maps for the XCAT phantom was reduced from 3.4 mm to 2.7 mm.
• Experimental data showed a 36% contrast increase with 2D lateral views compared to the range telescope method, with a mean absolute error of 0.4 mm for WET accuracy.

Conclusions:

• The proposed reconstruction framework with 2D lateral views significantly improves proton radiograph quality.
• This method is compatible with clinical beam settings and shows potential for adaptive proton therapy.