Liver Volume Variation Effect on SBRT Planning and Delivery for Upper Abdominal Malignancies

This study examines how the size of the liver changes between planning scans and actual radiation treatment sessions for patients receiving stereotactic body radiotherapy (SBRT) — a highly precise form of radiation — for tumors in the upper abdomen. Understanding liver volume changes helps doctors ensure radiation is delivered accurately. **You may be eligible if...** - You have a primary cancer of the pancreas, bile duct, or liver — or metastases in the liver, adrenal gland, or upper abdominal lymph nodes - You are planned to undergo SBRT (stereotactic body radiation therapy) **You may NOT be eligible if...** - You have previously received radiation therapy to the liver - You have a contraindication to IV contrast dye (such as kidney disease or contrast allergy that cannot be managed) - You are pregnant or breastfeeding, or cannot use adequate contraception during radiation - You are unable to fast before scans Talk to your doctor to see if this trial is right for you.