ABSTRACT
This chapter reviews the history of image-guided radiation therapy (IGRT), as well as its status and future directions. IGRT makes it is possible to widely implement cutting-edge technologies such as stereotactic ablative RT/stereotactic body RT, intensity-modulated RT (IMRT), volumetric modulated arc therapy (VMAT), and particle therapy in lung cancer, which typically presents as a moving target. Modern RT plays a crucial role in the management of lung cancer in definitive, neoadjuvant, and adjuvant settings. Four-dimensional computed tomography (4D-CT)-based motion management and volumetric image-based adaptive RT provide the basis for modern RT in lung cancer. 4D-CT only samples a snapshot of tumor motions on the simulation day; the motion and shape/volume can vary significantly at different times and on different days, particularly with the conventional 30 fractions of RT. Positron emission tomography (PET)/CT imaging upstaged and downstaged lung cancer in 25% of patients.
