Field output correction factors using a scintillation detector.

Area of Science:

• Medical Physics
• Radiation Oncology
• Detector Physics

Background:

• Accurate dosimetry is critical for small radiation fields in modern radiation therapy.
• Small field dosimetry presents challenges despite available detectors.
• The PRB-0002 plastic scintillation detector shows promise for simplifying these measurements.

Purpose of the Study:

• Adapt small field dosimetry formalism to plastic scintillation detectors.
• Utilize Monte Carlo (MC) simulations and experimental measurements.
• Characterize the PRB-0002 for accurate field output correction factor measurements and compare with other detectors.

Main Methods:

• Followed IAEA TRS-483 guidelines.
• Performed EGSnrc MC simulations of the PRB-0002, considering detector composition, surrounding materials, dose averaging, and ionization quenching.
• Determined field output correction factors using MC simulations and experimental validation against other detectors.

Main Results:

• PRB-0002 exhibits a balanced material composition and ionization quenching, yielding field output correction factors close to unity.
• For field sizes from 0.6x0.6 cm² to 30x30 cm², factors ranged from 1.002 to 0.999 with 0.5% uncertainty.
• An overall uncertainty of 0.59% was achieved for a 1x1 cm² field size using the PRB-0002.

Conclusions:

• The PRB-0002 is a near-ideal detector for small field dosimetry due to its field output correction factors near unity across various field sizes.
• This detector can accurately determine the field output correction factors of other dosimeters.
• Enhances quality assurance in radiation therapy through precise dosimetry.