Impact of respiratory motion on worst-case scenario optimized intensity modulated proton therapy for lung cancers.
Impact of respiratory motion on worst-case scenario optimized intensity modulated proton therapy for lung cancers.
复制标题
呼吸运动对肺癌的最坏情况优化强度调制质子治疗的影响。
DOI：
10.1016/j.prro.2014.08.002
复制
发表时间：
2015-03
影响因子：
3.3
通讯作者：
Mohan R
中科院分区：
文献类型：
--
作者：
Liu W;Liao Z;Schild SE;Liu Z;Li H;Li Y;Park PC;Li X;Stoker J;Shen J;Keole S;Anand A;Fatyga M;Dong L;Sahoo N;Vora S;Wong W;Zhu XR;Bues M;Mohan R
我们比较了常规优化的强度调制质子治疗（IMPT）治疗计划与最坏情况下优化的肺癌治疗计划。两种IMPT优化策略的比较集中在所得计划在患者设置、固有质子范围不确定性和呼吸运动引起的剂量扰动的影响下保持剂量目标的能力。对于9个肺癌病例中的每一个，以两种不同的方式创建了两个治疗计划，以说明治疗不确定性：第一种使用传统方法：将处方剂量输送到从内部靶体积（ITV）几何扩展的计划靶体积（PTV）。第二个采用了最坏情况下的优化方案，解决了设置和范围的不确定性，通过小波束优化。计算并比较了方案的最优性和鲁棒性。此外，通过比较吸气末和呼气末阶段的相应计划评价指标以及这些阶段之间的绝对差异，研究了两种策略下呼吸运动引起的患者解剖结构变化对剂量分布的影响。使用双侧配对t检验比较两组的平均计划评价指标。在不考虑呼吸运动的情况下，我们肯定了最坏情况下的优化上级基于PTV的常规优化计划的鲁棒性和最优性。考虑到呼吸运动，最差情况下的优化仍然实现了对靶区呼吸运动的更稳健剂量分布，以及相当或甚至更好的计划最优性[D95% ITV：96.6% vs 96.1%（p=0.26），D5%-D95% ITV：10.0% vs 12.3%（p=0.082），D1%脊髓：31.8% vs 36.5%（p =0.035）]。最差情况下的优化导致肺部IMPT的上级解决方案。尽管最坏情况下的优化没有明确说明呼吸运动，但它产生了抗运动的治疗计划。然而，需要进一步的研究，将呼吸运动到IMPT鲁棒优化。
We compared conventionally optimized intensity-modulated proton therapy (IMPT) treatment plans against the worst-case scenario optimized treatment plans for lung cancer. The comparison of the two IMPT optimization strategies focused on the resulting plans’ ability to retain dose objectives under the influence of patient set-up, inherent proton range uncertainty, and dose perturbation caused by respiratory motion. For each of the 9 lung cancer cases two treatment plans were created accounting for treatment uncertainties in two different ways: the first used the conventional method: delivery of prescribed dose to the planning target volume (PTV) that is geometrically expanded from the internal target volume (ITV). The second employed the worst-case scenario optimization scheme that addressed set-up and range uncertainties through beamlet optimization. The plan optimality and plan robustness were calculated and compared. Furthermore, the effects on dose distributions of the changes in patient anatomy due to respiratory motion was investigated for both strategies by comparing the corresponding plan evaluation metrics at the end-inspiration and end-expiration phase and absolute differences between these phases. The mean plan evaluation metrics of the two groups were compared using two-sided paired t-tests. Without respiratory motion considered, we affirmed that worst-case scenario optimization is superior to PTV-based conventional optimization in terms of plan robustness and optimality. With respiratory motion considered, worst-case-scenario optimization still achieved more robust dose distributions to respiratory motion for targets and comparable or even better plan optimality [D95% ITV: 96.6% versus 96.1% (p=0.26), D5% − D95% ITV: 10.0% versus 12.3% (p=0.082), D1% spinal cord: 31.8% versus 36.5% (p =0.035)]. Worst-case scenario optimization led to superior solutions for lung IMPT. Despite of the fact that worst-case-scenario optimization did not explicitly account for respiratory motion it produced motion-resistant treatment plans. However, further research is needed to incorporate respiratory motion into IMPT robust optimization.