Figure 1.

Case illustration of intensity modulated radiation therapy (IMRT): A 74-year-old male patient with recurrent oropharynx cancer presenting as a large right neck mass approximately 1 year after previously completing definitive chemoradiation to a dose of 70 Gy with concurrent cisplatin for ipsilateral p16-negative tonsil cancer. The patient was reirradiated to a dose of 66 Gy in 33 fractions over the course of 6 weeks with magnetic resonance image guided IMRT. The axial (A) and sagittal (B) sections of the IMRT treatment plan are displayed. The thick red line represents the prescription dose that encompasses the planning target volume (blue color wash), which comprised the gross tumor volume plus a 0.1 cm margin circumferentially. The green lines show the 105% hotspots. Notably, an effort was made to spare the ipsilateral uninvolved carotid artery (in pink) and spinal cord (in orange).