Electronic portal imaging vs kilovoltage imaging in fiducial marker image-guided radiotherapy for prostate cancer: an analysis of set-up uncertainties

Abstract

OBJECTIVES: The purpose of this study was to compare interfraction prostate displacement data between electronic portal imaging (EPI) and kilovoltage imaging (KVI) treatment units and discuss the impact of any difference on margin calculations for prostate cancer image-guided radiotherapy (IGRT). METHODS: Prostate interfraction displacement data was collected prospectively for the first 4 fractions in 333 patients treated with IGRT with daily pre-treatment EPI or KVI orthogonal imaging. Displacement was recorded in the anteroposterior (AP), left-right (LR) and superoinferior (SI) directions. The proportion of displacement EPI) were AP 1 mm, LR 1 mm and SI 0.5 mm. Wilcoxon rank-sum test showe..