A novel and fast method for proton range verification using a step wedge and 2D scintillator

Area of Science:

• Medical Physics
• Radiation Oncology
• Nuclear Instrumentation

Background:

• Proton therapy requires precise range verification for accurate dose delivery.
• Traditional methods like water tanks are time-consuming and labor-intensive.
• Need for faster, more efficient proton range verification techniques.

Purpose of the Study:

• To implement and evaluate a novel, fast method for proton range verification.
• Utilize a planar scintillator and step wedge for proton range measurements.
• Assess the accuracy, reproducibility, and sensitivity of the new method.

Main Methods:

• Designed a proton pencil beam plan with 35 energies delivered to a scintillator and step wedge.
• Repeated measurements 15 times over 3 days.
• Analyzed scintillator images, fitted Bragg peak regions, and calculated proton range using trigonometry.
• Verified accuracy against ionization chamber and water tank measurements.
• Evaluated reproducibility and sensitivity to range variations.

Main Results:

• Proton range accuracy within 0.2 mm for all 35 energies.
• High reproducibility with ±0.045 mm variation over 15 measurements.
• Sensitivity to range variation of 0.1 mm.
• Measurement of 35 proton ranges completed in under 3 minutes.
• Automated data processing provided immediate results.
• Setup time was less than 5 minutes.
• Time savings of approximately two orders of magnitude compared to water tank measurements.

Conclusions:

• A novel, fast, and sensitive method for proton range verification using a scintillator and step wedge was successfully implemented and evaluated.
• The method provides accurate and highly reproducible proton range measurements.
• This technique offers significant advantages in speed and efficiency for quality assurance in proton therapy.