Dose Imaging Detectors for Radiotherapy Based on Gas Electron Multipliers.

Area of Science:

• Medical Physics
• Radiation Detection
• Particle Therapy

Background:

• Advancements in charged particle therapy necessitate novel beam monitoring and 2D dosimetry systems.
• Accurate verification of dose distribution is crucial for modern dynamic beam delivery systems.

Purpose of the Study:

• To develop and evaluate dose imaging detectors based on gas electron multipliers (GEMs).
• To enhance dose measurement linearity, position, and timing resolution for pre-treatment verification and real-time monitoring in scanning beam therapy.

Main Methods:

• A prototype double-GEM detector (10x10 cm²) was tested using a 205 MeV proton beam.
• Evaluated both electronic cross-strip and optical readout modes for performance assessment.

Main Results:

• Electronic readout demonstrated fast response and 4 mm position resolution.
• Optical readout achieved a line spread function of σ=0.7 mm.
• Detector response remained linear up to 50 Gy/min, accurately representing Bragg peaks.

Conclusions:

• GEM-based detectors show promise for accurate 2D dosimetry in particle therapy.
• The developed detectors can improve dose verification and real-time monitoring for scanning beam systems.