title: Comparison of target coverage and dose to organs at risk between simultaneous integrated-boost whole-field intensity-modulated radiation therapy and junctioned intensity-modulated radiation therapy with a conventional radiotherapy field in treatment of nasopharyngeal carcinoma.
abstract: We have retrospectively investigated 15 nasopharyngeal carcinoma patients treated at our institution between March 2007 and August 2009. We used simultaneous integrated-boost whole field intensity-modulated radiation therapy (SIB WF-IMRT) to treat the entire planning target volume in the head and neck cancer. All of the SIB WF-IMRT plans were replanned by use of the junctioned intensity modulated radiation therapy (J-IMRT) technique for comparison. The effect on target coverage and sparing of organs at risk, including laryngeal sparing in the optimal SIB WF-IMRT plan was compared with that achieved with use of the J-IMRT technique. The mean larynx dose and standard deviation was 25.2 ± 5.8 Gy for SIB WF-IMRT and 19.8 ± 16.8 Gy for J-IMRT. A comparison between SIB WF-IMRT and the J-IMRT technique demonstrated that the larynx dose was increased in SIB WF-IMRT. However, when the strong dose constraint was applied to the larynx and the pseudo-volume was used for a steep dose fall-off immediately outside the target, the SIB WF-IMRT technique would have led to a larynx dose comparable to that achieved with J-IMRT. Therefore, in our current practice we use the SIB WF-IMRT technique, which does not have the problem of setup error at the match line for treatment of nasopharyngeal carcinoma.
authors.affiliation: Department of Radiation Oncology, Seoul National University Bundang Hospital, 303 Gumi-dong, Bundang-gu, Seongnam, Gyeonggi-do, Republic of Korea.
authors.forename: Jin-Beom
authors.initials: JB
authors.lastname: Chung
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Kim
authors.forename: In-Ah
authors.initials: IA
authors.lastname: Kim
authors.forename: Doo-Hyun
authors.initials: DH
authors.lastname: Lee
authors.forename: Yon-Lae
authors.initials: YL
authors.lastname: Kim
authors.forename: Kyoung-Sik
authors.initials: KS
authors.lastname: Choi
authors.forename: Bo-Young
authors.initials: BY
authors.lastname: Choe
authors.forename: Tae-Suk
authors.initials: TS
authors.lastname: Suh
mesh_terms: D001933:Brain Stem / Q000528:radiation effects; D002277:Carcinoma; D005123:Eye / Q000528:radiation effects; D005260:Female; D006801:Humans; D007830:Larynx / Q000528:radiation effects*; D008297:Male; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D009897:Optic Chiasm / Q000528:radiation effects; D009900:Optic Nerve / Q000528:radiation effects; D058958:Organs at Risk; D010306:Parotid Gland / Q000528:radiation effects; D010614:Pharynx / Q000528:radiation effects*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods* / Q000592:standards; D013116:Spinal Cord / Q000528:radiation effects