Comparison of VMAT vs dIMRT with fixed-jaw technique for postoperative radiotherapy of breast cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2018年第8期
- Page:
- 889-894
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Comparison of VMAT vs dIMRT with fixed-jaw technique for postoperative radiotherapy of breast cancer
- Author(s):
- HE Xiantao; WANG Zhanyu; TAN Junwen; LONG Yusong; LI Gang; FENG Yongfu
- Radiotherapy Treatment Room, Department of Oncology, Liuzhou Worker’s Hospital, Liuzhou 545005, China
- Keywords:
- ; Keywords: breast cancer; volumetric modulated arc therapy; dynamic intensity-modulated radiotherapy; fixed-jaw; dosimetry
- PACS:
- R730.55
- DOI:
- DOI:10.3969/j.issn.1005-202X.2018.08.005
- Abstract:
- Abstract: Objective To explore the dosimetric differences and technology features of volumetric modulated arc therapy (VMAT) and dynamic intensity-modulated radiotherapy (dIMRT) with fixed-jaws technique for postoperative radiotherapy of breast cancer. Methods Twenty breast cancer patients after radical surgery were selected, with 10 cases of left-sided breast cancer and 10 of right-sided breast cancer. Raystation 4.7.5 treatment planning system and Eclipse 11.0 treatment planning system were used to design VMAT plans and 7-field dIMRT plans, respectively, with a target prescription dose of 50 Gy/25 F. Moreover, the most appropriate fixed-jaw technology was applied for the two plans of each patient. The dosimetric differences, monitor units, treatment time and gamma passing rate in dose verification were compared. Results VMAT plans were better than dIMRT plans in the maximum dose, mean dose, and homogeneity index of target areas, and the dose homogeneity of the former was significantly improved, without hot spots in target areas. The minimum dose, conformity index and target coverage of VMAT plans and dIMRT plans were basically similar (P>0.05). Compared with dIMRT plans, VMAT plans showed significantly decreased radiotherapy dose of major organs-at-risk, such as the whole lung and heart, especially the V5, V20 of low dose region in the ipsilateral lung and the V30 of the heart. The total dose of normal tissue in VMAT plans was slightly higher than that in dIMRT plans. Compared with those in dIMRI plans, the average number of monitor units was reduced by an average of 59% per fraction, and the treatment time was reduced by an average of 60% per fraction in VMAT plans. The gamma passing rate of VMAT plans and dIMRT plans met the requirement of treatment (>95%). Conclusion Both VMAT and dIMRT meet the requirements of clinical prescription, but VMAT has more advantages. VMAT can not only provide better dose homogeneity, significantly reduce the total dose of major organs-at-risk, especially the low dose volume of lungs, but also obviously decrease monitor units and shorten treatment time.
Last Update: 2018-07-26