Evaluation of intensity-modulated radiotherapy using flattening filter free photon beams for patients with breast cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2017年第11期
- Page:
- 1086-1090
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Evaluation of intensity-modulated radiotherapy using flattening filter free photon beams for patients with breast cancer
- Author(s):
- WU Lili; ZHANG Jiyong; HUANG Baotian; LU Jiayang; LIN Zhu; ZHANG Wuzhe
- Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou 515041, China
- Keywords:
- ; breast cancer; high dose rate irradiation; flattening filter free mode; simultaneous integrated boost intensity-modulated radiotherapy
- PACS:
- R730.55；R815
- DOI:
- DOI:10.3969/j.issn.1005-202X.2017.11.002
- Abstract:
- Abstract: Objective To evaluate the feasibility of 6 MV photon beam with flattening filter free (FFF) applied on hypofractionated simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for patients receiving breast-conserving surgery for right-sided breast cancer. Methods The planning target volumes of tumor bed and breast (PTV1 and PTV2) of selected 10 patients treated with breast-conserving surgery for right-sided breast cancer were irradiated with 48 and 40 Gy in 15 fractions, respectively. For each case, SIB-IMRT plans with standard flattening filter (FF) mode and FFF mode were generated, respectively. The PTV coverage, conformity index (CI), homogeneity index, dose to organs-at-risk, monitor unit and delivery time were compared between FFF plan and FF plan. Results The differences between 2 plans in PTV coverage, homogeneity index and CI were within 1%. Compared with FF plan, FFF plan provided slightly higher D98% for PTV1 (t=-2.297, P<0.05), lower D90% and inferior CI for PTV2 (t=2.479, P=0.019; t=5.343, P<0.001). FFF plans also provided better sparing for V4 Gy and V16 Gy of ipsilateral lung, Dmean and D5% of contralateral breast, and lower mean dose, V5 Gy, V10 Gy and V20 Gy for normal tissue (t=2.318-11.535, P<0.05) as comparison with FF plan, while V40 Gy of normal tissue (t=-2.967, P=0.016) and skin mean dose (t=-6.102, P<0.001) were higher in FFF plan than in FF plan. Moreover, the monitor unit of FFF plans was significantly higher than that of FF plans [(1 417±230) vs (1 106±208); t=-8.220, P<0.001) ]. However, the delivery times of FFF plan were 33% less than that of FF plans (t=11.788, P<0.001). Conclusion Both FF plan and FFF plan meets the clinical requirements, but FFF plan is associated with a better organs-at-risk sparing, remarkably shorter treatment time and higher treatment efficiency.
Last Update: 2017-11-23