GSI Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt, Germany.
Phys Med Biol. 2018 Jan 17;63(2):025034. doi: 10.1088/1361-6560/aa9c62.
Intensity modulated particle therapy (IMPT) can produce highly conformal plans, but is limited in advanced lung cancer patients with multiple lesions due to motion and planning complexity. A 4D IMPT optimization including all motion states was expanded to include multiple targets, where each target (isocenter) is designated to specific field(s). Furthermore, to achieve stereotactic treatment planning objectives, target and OAR weights plus objective doses were automatically iteratively adapted. Finally, 4D doses were calculated for different motion scenarios. The results from our algorithm were compared to clinical stereotactic body radiation treatment (SBRT) plans. The study included eight patients with 24 lesions in total. Intended dose regimen for SBRT was 24 Gy in one fraction, but lower fractionated doses had to be delivered in three cases due to OAR constraints or failed plan quality assurance. The resulting IMPT treatment plans had no significant difference in target coverage compared to SBRT treatment plans. Average maximum point dose and dose to specific volume in OARs were on average 65% and 22% smaller with IMPT. IMPT could also deliver 24 Gy in one fraction in a patient where SBRT was limited due to the OAR vicinity. The developed algorithm shows the potential of IMPT in treatment of multiple moving targets in a complex geometry.
强度调制粒子治疗（IMPT）可以产生高度适形的计划，但由于运动和计划复杂性，在有多发性病变的晚期肺癌患者中受到限制。将包括所有运动状态的 4D IMPT 优化扩展到包括多个目标，其中每个目标（等中心点）指定给特定的场。此外，为了实现立体定向治疗计划目标，目标和 OAR 权重以及目标剂量会自动迭代适应。最后，针对不同的运动场景计算 4D 剂量。我们的算法结果与临床立体定向体部放射治疗（SBRT）计划进行了比较。该研究共包括 8 名患者，共 24 个病灶。SBRT 的预期剂量方案为 24Gy 一次，但由于 OAR 限制或计划质量保证失败，有 3 个病例必须采用分次剂量更低的方案。与 SBRT 治疗计划相比，IMPT 治疗计划在靶区覆盖方面没有显著差异。在 OAR 中，平均最大点剂量和特定体积剂量的平均降低了 65%和 22%。IMPT 还可以在由于 OAR 附近限制 SBRT 的情况下，为一名患者提供 24Gy 一次的剂量。开发的算法表明，IMPT 在治疗复杂几何形状中的多个移动目标方面具有潜力。
