Changes in Non-Small Cell Lung Cancer Tumor Location Secondary to Gastric Distension, Implications in the Context of Stereotactic Body Radiation Therapy

摘要

Objective: Stereotactic body radiation therapy (SBRT) facilitates highly conformal dose distributions to a target tumor volume. Accurate tumor localization is extremely important, and lung tumors pose a unique challenge due to respiratory motion. Patients are required to fast before PET/CT but not before CT simulation and daily treatment, introducing potential variability from gastric distension. Methods: A case was reviewed involving a patient with early-stage NSCLC which was simulated and treated with SBRT. PET/CT performed while fasting showed an isolated left lower lobe lesion. Following CT simulation, CT and PET/CT images were superimposed for comparison and treatment planning. Results: Tumor location variation was apparent following image superimposition. Simulation CT showed significant gastric distension compared to PET/CT. The patient was resimulated whilefasting, resulting in accurate and reproducible tumor localization for treatment planning. Conclusions: Gastric distension can alter tumor location and treatment volumes for radiotherapy planning, possibly resulting in inaccurate treatment administration.