文章：

儿童质子治疗中脾脏运动对全淋巴照射的交互影响效应

Interplay Effect of Splenic Motion for Total Lymphoid Irradiation in Pediatric Proton Therapy

原文发布日期：26 October 2023

DOI: 10.3390/cancers15215161

类型: Article

开放获取: 是

英文摘要：

(1) Background: The most significant cause of an unacceptable deviation from the planned dose during respiratory motion is the interplay effect. We examined the correlation between the magnitude of splenic motion and its impact on plan quality for total lymphoid irradiation (TLI); (2) Methods: Static and 4D CT images from ten patients were used for interplay effect simulations. Patients’ original plans were optimized based on the average CT extracted from the 4D CT and planned with two posterior beams using scenario-based optimization (±3 mm of setup and ±3% of range uncertainty) and gradient matching at the level of mid-spleen. Dynamically accumulated 4D doses (interplay effect dose) were calculated based on the time-dependent delivery sequence of radiation fluence across all phases of the 4D CT. Dose volume parameters for each simulated treatment delivery were evaluated for plan quality; (3) Results: Peak-to-peak splenic motion (≤12 mm) was measured from the 4D CT of ten patients. Interplay effect simulations revealed that the ITV coverage of the spleen remained within the protocol tolerance for splenic motion, ≤8 mm. The D100% coverage for ITV spleen decreased from 95.0% (nominal plan) to 89.3% with 10 mm and 87.2% with 12 mm of splenic motion; (4) Conclusions: 4D plan evaluation and robust optimization may overcome problems associated with respiratory motion in proton TLI treatments. Patient-specific respiratory motion evaluations are essential to confirming adequate dosimetric coverage when proton therapy is utilized.

摘要翻译： 

(1) 背景：呼吸运动导致计划剂量出现不可接受偏差的最主要原因是相互影响效应。本研究探讨了脾脏运动幅度与全淋巴照射计划质量之间的相关性；(2) 方法：采用十例患者的静态及四维CT图像进行相互影响效应模拟。基于四维CT提取的平均CT优化原始计划，采用双后野照射方案，通过基于场景的优化（±3 mm摆位误差及±3%射程不确定性）及脾脏中部层面的梯度匹配进行计划设计。根据四维CT各时相辐射注量随时间变化的递送序列，计算动态累积四维剂量（相互影响效应剂量）。通过评估每次模拟治疗递送的剂量体积参数来判定计划质量；(3) 结果：十例患者的四维CT显示脾脏峰间运动幅度≤12 mm。相互影响效应模拟表明，当脾脏运动≤8 mm时，脾脏内靶区的剂量覆盖仍符合方案耐受标准。脾脏内靶区的D100%覆盖率从基准计划的95.0%下降至脾脏运动10 mm时的89.3%及12 mm时的87.2%；(4) 结论：四维计划评估与鲁棒优化可克服质子全淋巴照射中呼吸运动相关问题。实施质子治疗时，个体化呼吸运动评估对确保足够的剂量覆盖至关重要。

原文链接：

Interplay Effect of Splenic Motion for Total Lymphoid Irradiation in Pediatric Proton Therapy