| Xia Wenlong,Chen Bo,Huang Peng,et al.Quantitative comparison of volumetric-modulated arc therapy plans for liver cancer using flattening filter-free and flattening filter modes based on plan quality metric (PQM)[J].Chinese Journal of Radiological Medicine and Protection,2018,38(9):680-683 |
| Quantitative comparison of volumetric-modulated arc therapy plans for liver cancer using flattening filter-free and flattening filter modes based on plan quality metric (PQM) |
| Received:April 10, 2018 |
| DOI：10.3760/cma.j.issn.0254-5098.2018.09.008 |
| KeyWords:Plan quality metric Flattening filter-free Liver cancer Volumetric modulated arc therapy Dosimetry |
| FundProject:国家重大研发计划项目（2016YFC0904600） |
| Author Name | Affiliation | E-mail | | Xia Wenlong | Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China | | | Chen Bo | Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China | | | Huang Peng | Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China | | | Dai Jianrong | Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China | dai_jianrong@cicams.ac.cn |
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| Abstract:: |
| Objective To quantitatively assess the plan quality of conventional fractionated volumetric modulated arc therapy (VMAT) plans for liver cancer treatments using flattening filter-free (FFF) and flattening filter (FF) modes based on plan quality metric (PQM). Methods A total of ten patients with liver tumor were selected. The patients were planned in FF and FFF mode of 6 MV X-ray respectively. The dose distribution of the planning target volume (PTV) and the organ at risk (OAR) were evaluated, and the monitor units (MUs) and the beam on time (BoT) were compared. According to the clinical requirements, a PQM with 16 submetrics was defined to evaluate the plan quality of the two modes. Results The maximal dose of FFF plan was less than that of FF plan (t=3.828, P<0.05). The normalized volume of 5 Gy (V5) and mean dose (Dmean) of the normal liver of FFF plan were lower than those of the FF plan (t=2.716, 3.007, P<0.05). The average MU of FFF plan[(574±130) MU] was higher than that of FF plan[(518±81) MU](t=-2.782,P<0.05), while the average BoT of FFF plan[(108±36)s] was significantly lower than that of FF plan[(160±29) s](t=6.767,P<0.05). The score of FFF plan was higher than that of FF plan (t=-2.746, P<0.05). Conclusions FFF mode can better protect the OAR at low dose levels. The MU of FFF mode plan were higher, but the beam on time was significantly lower than FF mode plan. With reference to the PQM evaluation criteria, the overall plan quality of the FFF mode was slightly higher. |
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