Fast In Situ Image Reconstruction for Proton Radiography

Area of Science:

• Medical Physics
• Radiation Oncology
• Imaging Technology

Background:

• Proton therapy offers precise dose delivery but faces range uncertainties due to indirect WEPL estimation.
• Current methods using X-ray Hounsfield units introduce 3-4% errors in proton range prediction.
• Accurate WEPL measurement is critical for preventing under- or overshooting the target, minimizing damage to healthy tissues.

Purpose of the Study:

• To develop and demonstrate a proton radiography system for direct, accurate 2D WEPL imaging.
• To enable rapid image acquisition and reconstruction for clinical applications.
• To improve patient alignment and range verification in daily proton therapy treatments.

Main Methods:

• Utilized Geant4 for simulating raw data from a prototype proton radiography system.
• Developed the pRad software for iterative reconstruction of proton radiographs.
• Employed a head phantom with known composition for simulation and validation.

Main Results:

• Achieved rapid radiograph reconstruction (11 seconds for 7.6 million protons) on standard hardware.
• Demonstrated mean WEPL errors of less than 1 mm in reconstructed head phantom images.
• Validated the system's capability for generating high-quality proton radiographs.

Conclusions:

• The developed proton radiography system and pRad software can generate high-quality proton radiographs.
• These radiographs are suitable for patient alignment and verification of water equivalent thickness.
• The system shows promise for enhancing the accuracy and safety of proton beam therapy.