Noise evaluation of Compton camera imaging for proton therapy

Area of Science:

• Medical Physics
• Particle Therapy
• Imaging Technology

Background:

• Compton cameras offer real-time dose monitoring in particle therapy by detecting prompt-gammas.
• Accurate image reconstruction relies on precise Compton cone calculations, often requiring multiple photon interactions.
• False events from neutrons and random coincidences degrade image quality and monitoring accuracy.

Purpose of the Study:

• To investigate the impact of false events (neutrons, random coincidences) on reconstructed images in Compton telescopes for particle therapy monitoring.
• To evaluate how these spurious events affect the determination of particle beam ranges.

Main Methods:

• A simulation study using FLUKA to model the complete detection chain, including false event generation.
• Event classification and image reconstruction using two- and three-event algorithms based on Maximum Likelihood Expectation Maximization.
• Analysis of neutron background and random coincidences under therapeutic-like beam conditions for mono-energetic proton beams.

Main Results:

• Simulations incorporated misidentified events (neutrons, random coincidences) into Compton telescope images.
• The study analyzed the effect of these false events on the accuracy of particle range determination from reconstructed images.
• The impact of neutron background and random coincidences was assessed for proton beams with realistic time structures.

Conclusions:

• False events significantly influence the quality of reconstructed images in Compton telescopes used for particle therapy.
• The presence of neutrons and random coincidences affects the accuracy of particle beam range estimations.
• Understanding and mitigating these spurious events is crucial for reliable real-time dose monitoring in particle therapy.