“…These factors include daily setup variations, primary tumour or nodal volume regression or progression, alteration in muscle mass and/or fat distribution, fluid shift within the body and weight loss [3,4]. If unnoticed or unattended, these changes might lead to discrepancies in dose delivery, namely underdosage of the target volume, with loss of tumour control, and/or to overdosage of the normal structures, potentially producing unexpected side effects [5,6]. In order to correct for day-to-day positioning errors relative to the p-CT, most centres perform Image Guided Radiotherapy (IGRT) where most of those mismatches are corrected through couch shifts.…”