[Comparison of dose accuracy between 2D array detectors for pre-treatment IMRT QA]

Area of Science:

• Medical Physics
• Radiation Oncology
• Dosimetry

Background:

• Accurate dose verification is critical in radiation therapy.
• Various 2D array detectors are available for clinical dosimetry.

Purpose of the Study:

• To compare the dosimetric properties of different 2D array detectors.
• To evaluate their accuracy in absolute dose and dose distributions for clinical treatment fields.

Main Methods:

• Comparison of dose linearity, dose rate dependence, and output factors.
• Evaluation of absolute dose and dose distribution accuracy using clinical fields.
• Analysis included MapCHECK, EPID, EPIDose, COMPASS, film, and ion chambers.

Main Results:

• Detector responses for dose linearity agreed within 1%.
• Dose rate dependence and output factors agreed within ±1.2% (except EPID).
• All 2D array detectors showed agreement within 5% with treatment planning systems (TPS) and >97% pass rates in gamma analysis (3 mm/3%).

Conclusions:

• All evaluated 2D array detectors demonstrate comparable accuracy for clinical fields.
• EPIDose offers superior resolution, making it suitable for small field dose distributions.
• These findings support the use of 2D array detectors for reliable dose verification in radiotherapy.