QC Test for intensity-modulated X-rays using gafchromic EBT3 film and 2D ion chamber array on a single linac

Accurate dosimetric verification is crucial in intensity-modulated radiotherapy (IMRT) to ensure precise dose delivery to target tissues while sparing surrounding healthy structures. This study aims to compare two widely used dosimetry tools-Gafchromic EBT3 film and the IBA MatriXX 2D ion chamber array-in terms of dose distribution accuracy and spatial resolution. A series of IMRT fields were delivered using an Elekta Synergy Platform linear accelerator, and planar dose distributions were measured using both systems. Gamma index analysis was conducted with 3%/3 mm and 2%/2 mm criteria. Results showed that both systems provided clinically acceptable agreement with planned distributions, although the Gafchromic film exhibited superior spatial resolution. These findings highlight the complementary rolls of film and ion chamber array dosimetry in modern radiotherapy QA.