THE EFFECTS OF RESPIRATORY MOTION ON THE IGRT PROCESS IN ESOPHAGEAL RADIOTHERAPY

Abstract

Radiotherapy treatment for esophageal cancer requires a daily cone-beam CT (CBCT) scan to ensure target accuracy for treatment. Respiratory motion is known to cause movement of the diaphragm, leading to challenges during image guidance radiation therapy (IGRT). This study quantified the displacement of the diaphragm during daily treatment to reference target displacement, as well as time taken to perform IGRT. Other IGRT factors were assessed. Results show a mean displacement of -0.9 (SD -0.6) cm in the y plane with no significant displacement in x or z. There was no correlation between displacement and IGRT duration, however males were associated with larger displacement in x (p=0.019), and non-smokers were associated with larger displacements in y and z (p<0.001). Future studies investigating respiratory motion reduction strategies are needed to identify the best approach moving forward.