Analysis of random and systematic errors in three dimensional conformal radiation therapy - a study at National Cancer Institute, Maharagama

Abstract

The aim of this study was to assess three dimensional set-up errors for three dimensional conformal radiation therapy (3-DCRT) at National Cancer Institute,Maharagama (NCIM). This study included 50 patients from each head and neck, brain and pelvic cases and 300 Portal images. Set-up errors were obtained by comparing Digitally reconstructed radiographs (DRR) and Electronic portal imaging device (EPID) images. The mean displacements for all images were compared using Kruskal-Wallis test analysis with the threshold ? = 0.05 which indicated significant differences within the major three axes. (Brain-p< 0.0001,Head and Neck-p= 0.001, pelvic-p< 0.0001). The values of portal verification for brain, head and neck and pelvic cases are within boundaries which are 88%, 83% and 78% respectively. The set-up margins were within tolerance for all three cases in all directions.