Nasopharynx cancer—involving the head and neck—is especially uncomfortable to treat because the patient must wear an aquaplast mask that is both claustrophobic and tight fitting in order to keep the area still. A male patient (65 years old) had his treatment shortened from 9 minutes, 25 seconds each day with conventional IMRT therapy to just 3 minutes, 3 seconds per session using RapidArc. The patient suffered much less discomfort with RapidArc since he only had to wear the mask and be still for one-third of the time.
The primary dose was to the nasopharynx and neighboring lymph nodes. The dose to the adjacent parotid gland was decreased by 30%. One side effect of irradiation to the parotid is dry mouth; less dosage to this area minimized this discomfort. Both brain stem and spinal cord doses were lower, as were doses to other normal tissues nearby.