Figure 1.

Patient with a right-sided T3N2b oropharyngeal tonsillar cancer, treated by definitive radiotherapy (RT). Anatomically corresponding axial contrast-enhanced CT images are shown, obtained just before and 6 months after completion of radiation treatment. (a, b) Level of oropharyngeal tonsil. Before RT (a), part of the oropharyngeal cancer is seen (arrows). After RT (b), the oropharyngeal tissues appear symmetrical. Volume reduction and increased enhancement of the parotid salivary glands (asterisks) correspond to radiation sialadenitis. (c, d) Level of tongue base. Before RT (c), asymmetry is seen in the tongue base tissues, appearing thicker on the right side; this corresponds to tumour extension along the tongue base, into the vallecula on the right side (arrows), and normal lingual tonsil on the left side (arrowheads). Several adenopathies are seen (asterisks). After RT (d), the tumoural tissue as well as the lingual tonsil disappeared. Also the adenopathies disappeared, leaving some strands of residual tissue (arrowhead). Note signs of radiation sialadenitis in both submandibular salivary glands (sm). (e, f) Level of hyoid bone. Before RT (e), several adenopathies are seen (asterisks). Note the normal appearance of submandibular salivary glands (sm), epiglottis (arrowhead) and ary-epiglottic folds (small arrowheads), pre-epiglottic fat plane (dots), and platysma muscles (arrows). After RT (f), the adenopathies disappeared; the submandibular salivary glands became smaller due to radiation sialadenitis. Thickening of the epiglottis and ary-epiglottic folds (arrowheads) is seen, as well as increased density in the pre-epiglottic space (dots). Note the thickening of the platysma muscles (arrows). (g, h) Level of false vocal cords. Before RT (g), adenopathy is seen on the right side (asterisk), as well as normal sized lymph node on the left side (arrowhead). After RT (h), both the adenopathies as the normal-appearing lymph node disappeared. Within the larynx, increased density is seen with the paraglottic spaces; the walls of the laryngeal ventricles appear thickened (arrows). There is also thickening and increased enhancement of the posterior hypopharyngeal walls (arrowheads). (i, j) Level of true vocal cords before (i) and after RT (j). Within the larynx, at this level very few changes are visible. The hypopharyngeal walls show slightly increased enhancement and thickening (arrowheads). More pronounced changes are visible within the anterior neck soft tissue, showing streaky infiltration of the fatty tissues, and platysma muscle thickening (arrows).