A dosimetric comparison of volumetric modulated arc therapy with intensity modulated radiation therapy for head and neck cancer
10.3760/cma.j.cn371439-20200224-00057
- VernacularTitle:头颈部肿瘤容积调强旋转放疗和适形调强放疗剂量学比较
- Author:
Wenchuan QIAN
1
;
Fan WANG
Author Information
1. 安徽医科大学第一附属医院放疗科，合肥 230022
- From:
Journal of International Oncology
2020;47(8):457-461
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To compare the dosimetric differences between volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) for head and neck cancer.Methods:From January 2019 to December 2019, 46 cases of patients with head and neck cancer confirmed by pathology in the First Affiliated Hospital of Anhui Medical University were selected. All patients underwent CT-simulation in supine position. Planning target volumes (PTVs) were delineated for two dose levels of PTV70 and PTV54 in 35 equal fraction. Simultaneous integrated boost plan was generated for all patients and optimized with both techniques, VMAT and IMRT with similar planning objectives. The dosimetry differences between the two plans were compared.Results:The conformity index (CI)95% of PTV70 in VMAT plan was higher than that in IMRT plan (0.91±0.02 vs. 0.86±0.06), and the difference was statistically significant ( t=4.933, P=0.004). The homogeneity index (HI)95% of PTV54 in VMAT plan was superior to that in IMRT (0.09±0.04 vs. 0.26±0.02), and the difference was statistically significant ( t=4.548, P=0.038). The spinal cord D 1% of VMAT was lower than that in IMRT (37.62±4.34 vs. 40.93±7.45), and the difference was statistically significant ( t=2.615, P=0.045). The dose of left parotid gland in VMAT was (21.28±8.13) Gy and the dose of right parotid gland was (22.39±7.42) Gy, which were slightly lower than those in IMRT [(22.73±11.42) Gy and (24.25±7.91) Gy], but the differences were not statistically significant ( t=0.703, P=0.322; t=1.134, P=0.315). Compared with IMRT, VMAT could significantly reduce the number of monitor units (521±112 vs. 2 129±564), and could significantly shorten the treatment time of patients [(2.12±0.39) min vs. (9.18±2.62) min], and the differences were statistically significant ( t=18.957, P<0.001; t=18.213, P<0.001). Conclusion:The dose distribution of VMAT technology is better than IMRT, the dose of organ at risk is reduced, the monitor unit is lesser, and the treatment time is shorter.
