18F-AraG PET/CT as a Non-Invasive Imaging Biomarker for Chemoradiation Treatment Response in Esophageal Cancer

This study is testing whether a special PET/CT scan using a new imaging agent called 18F-AraG can help doctors see how well chemotherapy and radiation are working against esophageal (food pipe) cancer. The scan is non-invasive and may help personalize treatment plans earlier in the process. **You may be eligible if...** - You are 18 or older - You have been diagnosed with locally advanced esophageal cancer (cancer of the food pipe) - Your tumor is larger than 2 cm and has not yet been treated - You are scheduled to receive chemotherapy combined with radiation as your primary treatment - If you can become pregnant, you agree to use effective birth control during the study and test negative for pregnancy before scans **You may NOT be eligible if...** - You are currently pregnant or breastfeeding - You are unwilling or unable to use contraception during the study Talk to your doctor to see if this trial is right for you.