RecruitingDietary supplementLiver Volume Variation Effect on SBRT Planning and Delivery for Upper Abdominal MalignanciesStandard planning constraints for liver SBRT incorporate strict dose-volume limits for normal liver parenchyma to minimize the risk of radiation-induced liver disease. The presence of diurnal and fasting/fed variations in liver volume therefore carry substantial potential for introducing errors into estimates of dose-volume distribution within normal liver tissue, as well as affecting day-to-day setup fidelity and organ alignment for treatment. This prospective study will examine how diurnal and fast-fed variations in liver volume affect treatment planning for abdominal SBRT.