부산대학교 도서관

The present study aimed to evaluate whether an adapted plan with Ethos[TM] could be used for pharyngeal cancer. Ten patients with pharyngeal cancer who underwent chemoradiotherapy with available daily cone-beam computed tomography (CBCT) data were included. Simulated treatments were generated on the Ethos[TM] treatment emulator using CBCTs every four to five fractions for two plans: adapted and scheduled. The simulated treatments were divided into three groups: early(first-secondweek), middle(third-fourthweek), andlate(fifth-seventhweek) periods. Dose-volume histogram parameters were compared for each period between the adapted and scheduled plans in terms of the planning target volume (PTV) ([D.sub.98%], [D.sub.95%], [D.sub.50%] and [D.sub.2%]), spinal cord ([D.sub.max] and [D.sub.1cc]), brainstem ([D.sub.max]) and ipsilateral and contralateral parotid glands ([D.sub.median] and [D.sub.mean]). The PTV [D.sub.98%], [D.sub.95%] and [D.sub.2%] of the adapted plan were significantly higher than those of the scheduled plans in all periods, except for [D.sub.98%] in the lateperiod. The adapted plan significantly reduced the spinal cord [D.sub.max] and [D.sub.1cc] compared with the scheduled plan in all periods. Ipsilateral and contralateral parotid glands [D.sub.mean] of the adapted plan were lower than those of scheduled plan in the late period. In conclusion, the present study revealed that the adapted plans could maintain PTV coverage while reducing the doses to organs at risk in each period compared with scheduled plans. Keywords: cone-beam computed tomography-guided online adaptive radiotherapy; adaptive radiotherapy; pharyngeal cancer; intensity modulated radiation therapy; whole neck irradiation; radiotherapy
INTRODUCTION The clinical use of intensity modulated radiation therapy (IMRT) represents a significant advancement in radiation oncology. IMRT is effective, especially in patients with head and neck cancer, because the [...]