| 徐源,马攀,徐英杰,门阔,戴建荣.一种确定立体定向放疗VMAT计划处方等剂量线的方法[J].中华放射医学与防护杂志,2020,40(6):477-480 |
| 一种确定立体定向放疗VMAT计划处方等剂量线的方法 |
| A method of determining the prescription isodose line for stereotactic radiotherapy VMAT plan |
| 投稿时间：2019-09-24 |
| DOI：10.3760/cma.j.issn.0254-5098.2020.06.011 |
| 中文关键词: 立体定向放疗 处方等剂量线 VMAT 脑转移瘤 |
| 英文关键词:Stereotactic radiotherapy Prescription isodose line VMAT Brain metastases |
| 基金项目:国家自然科学基金（11875320） |
|
| 摘要点击次数: 1896 |
| 全文下载次数: 923 |
| 中文摘要: |
| 目的 建立一种确定立体定向放疗（SRT）容积调强弧形治疗（VMAT）计划处方等剂量线（IDL）的方法。方法 选取8例SRT脑转移瘤患者，靶区体积范围3.5~11.7 cm3（中位数6.1 cm3）。采用VMAT技术，首先对每一个靶区设计相同处方剂量的参考计划。然后，采用原靶区内收一定几何边界生成的新靶区来进行优化计算，从而得到不同IDL的计划。研究不同靶区达到最优IDL范围所需内收的最小几何边界。结果 所有靶区达到最优IDL范围所需内收的最小边界均为4或5 mm，其得到的平均IDL为（66.05±0.02）%。最优IDL计划同参考计划相比，平均梯度指数（GI）从4.05±0.39下降到3.37±0.24，下降了20%（Z=-2.521，P<0.05）。正常脑组织中V40、V30、V5以及平均剂量分别下降了11.5%（Z=-1.973，P<0.05）、7.2%（Z=-2.105，P<0.05）、12.8%（Z=-2.521，P<0.05）以及8.1%（Z=-2.382，P<0.05），V20、V10以及适形度指数无明显差异（P>0.05）。结论 采用靶区内收生成新的靶区进行计划设计的方法可以用于SRT-VMAT计划IDL的优化。靶区内收4或5 mm进行计划设计可以使IDL达到最优范围，从而可以降低GI值以及更好地保护正常脑组织。 |
| 英文摘要: |
| Objective To establish a method of determining the prescription isodose line for steretactic radiotherapy (SRT) volumetric modulated arc radiotherapy (VMAT) plan. Methods Eight patients with brain metastases treated with SRT were enrolled. The volume of planning target volume (PTV) ranged from 3.5 to 11.7 cm3 (median 6.1 cm3). Reference VMAT plans were designed for each patient with identical prescription dose. Then, the original PTV was contracted by a few millimeters to form a new target for optimization to get plans with different IDLs. The minimum margin which was needed to be contracted to achieve optimal IDL range for each PTV was also studied. Results To achieve the optimal IDL range, 4 or 5 mm PTV contraction was needed for all patients, and the average IDL was (66.05±0.02)%. Compared with reference plans, the average gradient index (GI) of optimal IDL plans decreased by 20% from 4.05±0.39 to 3.37±0.24 (Z=-2.521, P<0.05). The V40, V30, V5 and mean dose in normal brain tissue decreased by 11.5% (Z=-1.973, P<0.05), 7.2% (Z=-2.105, P<0.05), 12.8% (Z=-2.521, P<0.05) and 8.1%, respectively (Z=-2.382, P<0.05), and there was no statistically significant difference with V20, V10 and conformity index (P>0.05). Conclusions The optimization of IDL for SRT-VMAT plan can be achieved with the method of contracting PTV to form new target for planning. 4 or 5 mm is needed to be contracted to achieve the optimal IDL range, and to get lower GI and protect the normal brain tissue. |
| HTML 查看全文 查看/发表评论 下载PDF阅读器 |
| 关闭 |
|
|
|