Use of Respiratory-Correlated Four-Dimensional Computed Tomography to Determine Acceptable Treatment Margins for Locally Advanced Pancreatic Adenocarcinoma

These data suggest that an asymmetric expansion of 1.0, 0.7, and 0.6 cm along the respective SI, anteroposterior, and medial-lateral directions is recommended if a respiratory-correlated four-dimensional computed tomography scan is not available to evaluate the tumor motion during treatment planning. Surrogates of tumor motion, such as biliary stents or external markers, should be used with caution.