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

Figure 1

The positions of the hyoid and thyroid cartilages can change noticeably during the simulation or treatment delivery. Because the swallowing action is usually infrequent and has a short duration, a simulation CT could be biased towards an infrequent anatomical pose by the consequence of swallowing. If the hyoid and thyroid cartilages are captured at their most inferior positions (top row), the larynx may receive higher dose during treatment. In the converse situation, if the hyoid and thyroid cartilages are captured at their most superior positions during CT simulation (bottom row), a primary target near the base of tongue could be underdosed during treatment.