Uniformity Correction of Large-Area XY - Strip Detector with Multi-Leaf Collimator

The evolution of photon therapy technology has driven the trend of using large-area detectors as quality assurance tools. Large-area XY strip detectors have the advantage of high resolution with less channel readouts. However, the overall output of large-area XY strip detectors must maintain an accuracy within 1% to meet quality assurance requirements. This study utilized a medical linear accelerator (LINAC) and a multi-leaf collimator (MLC) slit to generate a strip-shaped radiation source. The XY strip detector's readouts in two directions were obtained after MLC slit scan and generates LUT, a lookup table (LUT) method was employed in data analysis to correct errors introduced by various factors. Two tests were conducted: (1) Table test : To verify accuracy of LUT and; (2) Daily Quality assurance (QA) testing of a 10 cm x 10 cm square field for seven different types of beams to evaluate the effect of LUT correction. The LUT method proposed in this study is easy to implement and effectively reduces the relative errors of a large-area detector (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$28 \times 30 ~\text{cm}$</tex>) to approximately 1%.