| Summary: | Background: The aim of this study was to compare the dosimetric parameters of 9 field intensity modulated radiotherapy (9F-IMRT) and two kinds of volumetric modulated arc therapy (VMAT) for postoperative cervical cancer patients with paraaortic lymph node (PALN) metastasis, and to provide the reasonable selection of the cervical cancer patients with para-aortic lymph node metastasis who need postoperative radiotherapy in clinic.
Methods: Fifteen patients of postoperative cervical cancer patients with para-aortic lymph node metastasis were planed with the same dose prescription and optimization parameters by means of 9-field IMRT (9F-IMRT), a single arc (Arcl) and dual arc (Arc2) VMAT, respectively. The dosimetric differences of planning target volume (PTV), organs at risk(OAR), the number of monitor units (MUs) and treatment time were compared among the three treatment plans.
Results: The conformity index (CI) and the homogeneity index (HI) of PTV for Arc2 plans were superior to 9F-IMRT (P < 0.05). The V40, V50 of the rectum, V50 of the intestine, bladder and femoral head for Arc2 plans were better than 9F-IMRT plans. V50 of the femoral head and the mean dose of kidney for Arc1 and Arc2 plans were all better than 9F-IMRT plans. The number of MUs of 9F-IMRT plans (1,105.27 ± 107.12) was significantly higher than the Arc1 plans (755.23 ± 225.98) and Arc2 plans (967.24 ± 198.41), the difference was statistically significant (F = 12.736, P < 0.01). The treatment time of 9F-IMRT plans (430.47 ± 36.45) was significantly higher than the Arc1 plans (304.20 ± 48.42) and Arc2 plans (332.93 ± 47.62), the difference was statistically significant (F = 33.180, P < 0.01).
Conclusion: Compared to 9F-IMRT, Arc1 and Arc2 plans can better to meet the clinical requirements for the postoperative cervical cancer patients with para-aortic lymph node metastasis. And the Arc2 VMAT plans is superior to Arc1 VMAT plans, there will significantly improve the treatment efficiency.
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