3D prompt gamma imaging for proton beam range verification.

Area of Science:

• Medical Physics
• Nuclear Instrumentation
• Radiation Oncology

Background:

• Proton therapy offers precise dose delivery but requires accurate range verification.
• Prompt gamma imaging presents a promising method for real-time monitoring of the proton path.
• Current imaging techniques may have limitations in spatial resolution and real-time feedback.

Purpose of the Study:

• To assess the capability of a single Compton camera (CC) for 3D prompt gamma (PG) imaging.
• To evaluate PG imaging performance under clinical proton beam delivery conditions.
• To determine the feasibility of using CC for proton range verification in real-time.

Main Methods:

• A prototype Compton camera was used to measure PGs from a tissue-equivalent phantom irradiated with proton pencil beams.
• Measurements were conducted at various locations along the beam path for hypo-fractionated and standard dose scenarios.
• Data were aggregated to simulate a clinical-scale CC for evaluating Bragg peak shifts.

Main Results:

• The Compton camera successfully visualized the distal end of the Bragg peak up to 4 cm away.
• 3D PG images were generated with as few as 1x10^8 protons.
• Shifts in proton beam range as small as 2 mm were detectable for a 2 Gy dose.

Conclusions:

• A single Compton camera is capable of 3D prompt gamma imaging for proton range verification.
• This imaging approach is feasible under clinical proton beam delivery conditions.
• The technology holds potential for enhancing the safety and efficacy of proton therapy.