| Liu Lingling,Fei Zhenle,Li Bingbing,Xia Li,Zhang Liwei,Wang Hongzhi.Effect of respiratory amplitude on the dose distribution of volumetric modulated arc therapy[J].Chinese Journal of Radiological Medicine and Protection,2016,36(3):220-224 |
| Effect of respiratory amplitude on the dose distribution of volumetric modulated arc therapy |
| Received:October 25, 2015 |
| DOI：10.3760/cma.j.issn.0254-5098.2016.03.012 |
| KeyWords:Respiratory movement amplitude Volumetric modulated arc therapy (VMAT) Dose distribution Respiratory motion simulation phantom (QUASAR) |
| FundProject: |
| Author Name | Affiliation | E-mail | | Liu Lingling | Cancer Hospital, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China | | | Fei Zhenle | Radiotherapy Center, Chinese People's Liberation Army 105 Hospital, Hefei 230031, China | feizhenle@21cn.com | | Li Bingbing | Cancer Hospital, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China | | | Xia Li | Cancer Hospital, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China | | | Zhang Liwei | Cancer Hospital, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China | | | Wang Hongzhi | Cancer Hospital, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China | |
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| Abstract:: |
| Objective To study the effect of the respiratory amplitude on the dose distribution of volumetric modulated arc therapy (VMAT). Methods Respiratory motion simulation phantom (QUASAR) was used to simulate the respiratory movement from head to toe, and a two-dimensional ionization chamber matrix was used to collect the dose distribution in isocenter with different respiratory amplitude. Verisoft software and absolute dose analysis were used to analyze dose distribution, percentage errors of absolute dose in isocenter, passing rates of radiation field for the data collected, and results were compared to planned dosage. Results The effect on isocenter target dose of respiratory motion was below dose tolerance 5% (t=-22.614~-10.756, P<0.05). The respiratory movement made the dose on the edge of the target area higher, with fewer hot spots and more cold spots in the target area. As the respiratory amplitude increased, the effect of respiratory movement on the overall dose distribution in the target area was greater. The difference of the whole beam γ passing rate between 6, 8, 10 mm and stationary state was significant (t=3.095, 8.685, 14.096, P<0.05). The difference of target γ passing rate between 8, 10 mm and stationary state was significant (t=6.081, 9.841, P<0.05). Conclusions The respiratory movement could cause the dose transmission errors of VMAT, the error increased with increased range of motion. The actual radiation dose for normal tissues along the direction of respiratory movement on the target edge was higher than what was planned. |
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