Sensitivity analysis of key radiotherapy cost drivers: total costs per course and percentage deviation from base case estimates (in brackets), by number of fractions per course (2012€). a. variations in treatment time (Treatment time refers to the time taken per radiotherapy session per procedure. 15 minutes relates to current practice). b. variations in capacity utilization (Capacity utilization refers to the time both labor and capital operate in the radiotherapy department on a given day. 100% relates to current working hours). c. variations in staff numbers (Staff numbers refers to the number of personnel per linear accelerator per procedure. Four staff members per linear accelerator relates to current practice). d. variations in overheads (Overheads refers to the costs of accommodation, utilities (light, heat and telephone), support and back-office staff and training for radiotherapy. 40% relates to Irish current recommendations on the costing of overheads in relation to direct salary costs).