Aims:To compare flattening filter free(FFF)beams of tomotherapy(TOMO)and C-arm based flattening filter free beams in volumetric modulated arc therapy(VMAT)of cervical cancer after surgery through a retrospective planning study.Materials and Methods:For a cohort of 15 patients,Tomotherapy and VMAT plans of FFF beams were designed.The prescribed dose was 45Gy/1.8Gy/25f,95%of the planning target volume received this dose.Doses were computed with a commercially available TPS using Monte Carlo(MC)algorithm and convolution and superposition algorithm,respectively.Plans were compared according to dose-volume histogram(DVH)analysis in terms of PTV homogeneity and conformity indices(HI and CI)as well as OARs dose and volume parameters.Results:TOMO was superior to C-arm based VMAT in terms of HI and CI.Statistically significant differences were observed between TOMO and VMAT in terms of V20 of pelvic bone marrow(p=0.046),V40 of rectum(p=0.004)and V10 of normal tissue(p=0.000)while no significant difference were observed for other dosimetric parameters(p>0.05).C-arm based VMAT improved the treatment delivery efficiency compared with TOMO(p=0.000).Conclusions:For patients with cervical cancer after hysterectomy,TOMO achieved superior target uniformity and coverage while reduction of treatment time of C-arm based VMAT in cerval cancer is beneficial.Then,a trade-off may be found in selecting radiation technique in routine clinical work.