Adaptive Radiation Therapy for Head and Neck Cancer—Can an Old Goal Evolve into a New Standard?

Figure 5

Region-of-interest (ROI) selection for H and N IGRT should be based on clinical goals and is ideally located in proximity to critical clinical target volumes and/or normal structures requiring strict sparing. The top row shows a base-of-tongue cancer in which the C2 vertebral body was selected as an alignment object close to both GTV and spinal cord. For a sinus cancer case (bottom row), the PTV was used as the alignment ROI for patient setup to optimize coverage of high-risk CTVs and sparing of closely neighboring neural tissues.