title: RapidArc radiotherapy for whole pelvic lymph node in cervical cancer with 6 and 15 MV: a treatment planning comparison with fixed field IMRT.
abstract: Dosimetric differences were investigated among single and dual arc RapidArc and fixed-field intensity-modulated radiotherapy (f-IMRT) treatment plans for whole pelvic irradiation of lymph nodes. A total of 12 patients who had undergone radical surgery for cervical cancer and who had demonstrated multiple pelvic lymph node metastases were treated with radiotherapy. For all 12 cases, 7-field IMRT, single-arc RapidArc and dual-arc RapidArc were applied with 6 MV and 15 MV X-ray energies. The radiation dosimetric parameters for the different plans were compared with one another. All the plans met the clinical requirements. The homogeneity, conformity and external volume indices of f-IMRT and dual-arc RapidArc were better than for single-arc RapidArc (P < 0.05), while the differences between f-IMRT and dual-arc RapidArc were not significant. There were no significant differences in the radiation dose to organs at risk, except for the small bowel receiving >40 Gy (f-IMRT and dual-arc < single-arc, P < 0.05). The differences in dose distributions between the two applied X-ray energies for each of the modality plans were not significant. RapidArc plans resulted in fewer monitor units than the corresponding f-IMRT plans. Also, there were no differences between the two photon energies, except for a reduction in the number of MUs for 15 MV (P > 0.05). Compared to f-IMRT, no significant dosimetric benefits were found using RapidArc for whole pelvic lymph node irradiation. However, RapidArc has been associated with shorter treatment time and fewer monitor units, supporting the case for its safety and efficacy for pelvic irradiation.
authors.affiliation: Department of Radiation Physics, Shandong Cancer Hospital and Institute, 440 Jiyan Road, Jinan, Shandong Province 250117, China.
authors.forename: De-Yin
authors.initials: DY
authors.lastname: Zhai
authors.forename: Yong
authors.initials: Y
authors.lastname: Yin
authors.forename: Guan-Zhong
authors.initials: GZ
authors.lastname: Gong
authors.forename: Tong-Hai
authors.initials: TH
authors.lastname: Liu
authors.forename: Jin-Hu
authors.initials: JH
authors.lastname: Chen
authors.forename: Chang-Sheng
authors.initials: CS
authors.lastname: Ma
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D010388:Pelvis / Q000528:radiation effects; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy* / Q000556:secondary*