Dynamic gating window technique for the reduction of dosimetric error in respiratory-gated spot-scanning particle therapy: An initial phantom study using patient tumor trajectory data
Dynamic gating window technique for the reduction of dosimetric error in respiratory-gated spot-scanning particle therapy: An initial phantom study using patient tumor trajectory data
复制标题
用于减少呼吸门控点扫描粒子治疗中剂量误差的动态门控窗口技术：使用患者肿瘤轨迹数据进行的初步模型研究
DOI：
10.1002/acm2.12832
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发表时间：
2020
影响因子：
2.1
通讯作者：
Kikuo Umegaki
中科院分区：
文献类型：
--
作者：
Naoki Miyamoto;Kouhei Yokokawa;Seishin Takao;Taeko Matsuura;Sodai Tanaka;Shinichi Shimizu;Hiroki Shirato;Kikuo Umegaki
与被动散射照射技术相比，点扫描粒子治疗具有靶标符合度高、能量利用效率高等优点。然而，这种辐照技术对目标运动敏感。在目前的临床情况下，一些运动管理技术，例如使用外部或内部替代物的呼吸门控照射，已经应用于临床。在基于替代的门控中，门控窗口的大小在当前治疗系统的治疗过程中是固定的。在本研究中，我们提出了一种动态选通窗口技术，该技术通过考虑可能的剂量测定误差来优化每个点的选通窗口的大小。通过使用水体模中的移动目标模拟辐照来评估动态选通窗口技术的有效性。在剂量学特性比较中，与固定门方法相比，动态门窗口技术在不同有效深度的所有评估体积中表现出更好的性能。与固定门相比，动态门中剂量测定特性随目标深度的变化较小。这些结果表明，无论目标深度如何，动态选通窗口技术都可以保持可接受的剂量分布。动态门的总体选通效率大约等于或大于固定选通窗口的总选通效率。在动态选通中，随着目标深度变浅，选通效率将会降低，尽管无论目标深度如何都会保持剂量测定特性。这项研究的结果表明，所提出的门控技术可能会改善剂量分布。然而，未来应进行额外的评估，通过假设治疗系统的规格和临床情况来确定临床适用性。
Spot‐scanning particle therapy possesses advantages, such as high conformity to the target and efficient energy utilization compared with those of the passive scattering irradiation technique. However, this irradiation technique is sensitive to target motion. In the current clinical situation, some motion management techniques, such as respiratory‐gated irradiation, which uses an external or internal surrogate, have been clinically applied. In surrogate‐based gating, the size of the gating window is fixed during the treatment in the current treatment system. In this study, we propose a dynamic gating window technique, which optimizes the size of gating window for each spot by considering a possible dosimetric error. The effectiveness of the dynamic gating window technique was evaluated by simulating irradiation using a moving target in a water phantom. In dosimetric characteristics comparison, the dynamic gating window technique exhibited better performance in all evaluation volumes with different effective depths compared with that of the fixed gate approach. The variation of dosimetric characteristics according to the target depth was small in dynamic gate compared to fixed gate. These results suggest that the dynamic gating window technique can maintain an acceptable dose distribution regardless of the target depth. The overall gating efficiency of the dynamic gate was approximately equal or greater than that of the fixed gating window. In dynamic gate, as the target depth becomes shallower, the gating efficiency will be reduced, although dosimetric characteristics will be maintained regardless of the target depth. The results of this study suggest that the proposed gating technique may potentially improve the dose distribution. However, additional evaluations should be undertaken in the future to determine clinical applicability by assuming the specifications of the treatment system and clinical situation.