Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Molecular Imaging, Radiotherapy and Oncology (MIRO), Brussels, Belgium; Cliniques Universitaires Saint Luc, Department of Radiation Oncology, Brussels, Belgium.
Université Catholique de Louvain, ImagX-R, Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Louvain-La-Neuve, Belgium.
Radiother Oncol. 2019 Apr;133:132-139. doi: 10.1016/j.radonc.2018.12.026. Epub 2019 Jan 25.
When using highly conformal radiotherapy techniques, a stabilized breathing pattern could greatly benefit the treatment of mobile tumours. Therefore, we assessed the feasibility of Mechanically-assisted non-invasive ventilation (MANIV) on unsedated volunteers, and its ability to stabilize and modulate the breathing pattern over time.
Twelve healthy volunteers underwent 2 sessions of dynamic MRI under 4 ventilation modes: spontaneous breathing (SP), volume-controlled mode (VC) that imposes regular breathing in physiologic conditions, shallow-controlled mode (SH) that intends to lower amplitudes while increasing the breathing rate, and slow-controlled mode (SL) that mimics end-inspiratory breath-holds. The last 3 modes were achieved under respirator without sedation. The motion of the diaphragm was tracked along the breathing cycles on MRI images and expressed in position, breathing amplitude, and breathing period for intra- and inter-session analyses. In addition, end-inspiratory breath-hold duration and position stability were analysed during the SL mode.
MANIV was well-tolerated by all volunteers, without adverse event. The MRI environment led to more discomfort than MANIV itself. Compared to SP, VC and SH modes improved the inter-session reproducibility of the amplitude (by 43% and 47% respectively) and significantly stabilized the intra- and inter-session breathing rate (p < 0.001). Compared to VC, SH mode significantly reduced the intra-session mean amplitude (36%) (p < 0.002), its variability (42%) (p < 0.001), and the intra-session baseline shift (26%) (p < 0.001). The SL mode achieved end-inspiratory plateaus lasting more than 10 s.
MANIV offers exciting perspectives for motion management. It improves its intra- and inter-session reproducibility and should facilitate respiratory tracking, gating or margin techniques for both photon and proton treatments.
在使用高度适形放疗技术时，稳定的呼吸模式可以极大地有益于移动肿瘤的治疗。因此，我们评估了机械辅助无创通气（MANIV）在未镇静志愿者中的可行性，以及其随时间稳定和调节呼吸模式的能力。
12 名健康志愿者在 4 种通气模式下进行了 2 次动态 MRI 检查：自主呼吸（SP）、在生理条件下强制进行有规律呼吸的容量控制模式（VC）、旨在降低幅度同时增加呼吸频率的浅控模式（SH）、模仿吸气末屏气的慢控模式（SL）。后 3 种模式是在没有镇静的情况下通过呼吸机实现的。在 MRI 图像上沿呼吸周期跟踪膈肌的运动，并在个体内和个体间分析中表示为位置、呼吸幅度和呼吸周期。此外，还在 SL 模式下分析了吸气末屏气的持续时间和位置稳定性。
MANIV 被所有志愿者耐受良好，无不良反应。MRI 环境比 MANIV 本身更令人不适。与 SP 相比，VC 和 SH 模式分别提高了幅度的个体内和个体间可重复性（分别提高了 43%和 47%），并显著稳定了个体内和个体间的呼吸频率（p<0.001）。与 VC 相比，SH 模式显著降低了个体内平均幅度（36%）（p<0.002）、变异性（42%）（p<0.001）和个体内基线偏移（26%）（p<0.001）。SL 模式实现了持续超过 10s 的吸气末平台。
MANIV 为运动管理提供了令人兴奋的前景。它提高了个体内和个体间的可重复性，应该有利于光子和质子治疗的呼吸跟踪、门控或边缘技术。
