title: Dosimetric evaluation of magnetic resonance imaging-based intracavitary brachytherapy for cervical cancer.
abstract: The purpose of this study was to evaluate the dosimetric benefit of magnetic resonance imaging (MRI)-based dose adaptation in intracavitary brachytherapy (ICR) for cervical cancer. Dose-volume histograms were compared between matched conventional and optimized plans in 22 patients who were treated by MRI-based ICR. Doses to organs-at-risk (OAR) and dose covering 90% of high-risk clinical target volume (HR-CTV) were evaluated to compare OAR sparing and target coverage, respectively. The probability of RTOG rectal toxicity grade of ≥2 in the 22 patients was estimated based on the prediction model generated from previous three-dimensional CT-based ICR data. After optimization, doses to OAR showed a statistically significant decrease. The reduction percentage (reduced dose by optimization x 100/dose in the conventional plan) was higher in patients with HR-CTV >20 cc than in patients with HR-CTV >20 cc in the rectum. In patients with HR-CTV ≤ 20 cc, the mean probability of RTOG rectal toxicity grade ≥ 2 was 67.6% for the conventional plan and 47.8% for the optimized plan, based on the prediction model. In conclusion, dose adaptation by MRI-based ICR for cervical cancer resulted in significant dose reduction to the rectum, especially in patients with HR-CTV ≤ 20 cc.
authors.affiliation: Research Institute and Hospital, National Cancer Center, Goyang, Korea. jooyoungcasa@ncc.re.kr.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: J Y
authors.initials: JY
authors.lastname: Kim
authors.forename: T H
authors.initials: TH
authors.lastname: Kim
authors.forename: Y K
authors.initials: YK
authors.lastname: Lim
authors.forename: M G
authors.initials: MG
authors.lastname: Yoon
authors.forename: J N
authors.initials: JN
authors.lastname: Joo
authors.forename: S Y
authors.initials: SY
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D005260:Female; D006470:Hemorrhage; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011859:Radiography; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012007:Rectum / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*