Novel imaging and treatment technologies for image-guided noninvasive stereotactic cardiac radiosurgery

摘要 室性心动过速(VT)引起的心脏性猝死(SCD)每年导致15万人死亡。 在美国，无创立体定向心脏放射外科(NSCR)最近被报道为一种新的和 替代非侵入性治疗方案治疗对标准药物和导管消融无效的室性心动过速 治疗(Cuculich和Robinson，《新英格兰医学杂志》，2017年12月)。对5名患者的初步结果显示99.9% 6周后室性心动过速发作减少，导致2016-2018年进行I/II期临床试验 (ClinicalTrials.gov NCT02919618)。I/II期试验的初步结果显示了类似的疗效 (出版待定)到最初的试点研究。目前，目标卷的大小是 致心律失常的组织，以确保治疗剂量在存在的情况下被输送到心脏病变 心脏和呼吸运动。尽管有证据支持有效性，但最重要的是将 不必要地接受高剂量辐射治疗的健康心脏组织体积，以降低 晚期并发症(包括心包炎、心绞痛、心肌梗死和动脉粥样硬化加速)。 我们这项研究的临床目标是：1)提高将辐射束引导到 2)减少对心脏周围健康组织的辐射毒性， 肺和食道；3)提高NSCR的整体疗效。这些目标将是 使用新的放射治疗工艺、目标清晰度、成像、图像制导、 目标运动跟踪和预测，以及辐射传输选通方法。新型磁共振成像和锥形波束 将开发CT(CBCT)图像采集和重建方法，以表征和 补偿心脏和呼吸运动，并显著提高目标清晰度和运动 NSCR的管理组件。将开发新的NSCR治疗工艺，以减少 患者设置在治疗日的不确定性，并通过以下方式提高放射传输的准确性 基于实时目标位置和目标位置的目标运动跟踪和辐射波束选通 呼吸+心电信号。在此基础上开发和测试的新的治疗和成像方法 这项研究将同时适用于MRI引导的放射传递系统(MR-LINACS)和CBCT图像 引导辐射传输系统(CBCT-LINACS)。

Abstract Sudden cardiac death (SCD) caused by ventricular tachycardia (VT) results in >150,000 deaths/year in the U.S. Noninvasive Stereotactic Cardiac Radiosurgery (NSCR) was recently reported as a novel and alternative noninvasive treatment option to treat VT refractory to standard drug and catheter ablation therapy (Cuculich and Robinson, NEJM, Dec. 2017). The initial results for five patients resulted in a 99.9% reduction of VT episodes after 6 weeks, leading to a Phase I/II clinical trial in 2016-2018 (ClinicalTrials.gov NCT02919618). The preliminary results of Phase I/II trial showed similar efficacy (publication is pending) to the initial pilot study. Currently, the target volume is ~3 times larger than the arrhythmogenic tissue to ensure the therapeutic dose is delivered to the cardiac lesion in the presence of cardiac and respiratory motion. Despite evidence supporting efficacy, it is essential to minimize the volume of healthy cardiac tissue unnecessarily treated to high radiation doses to reduce the likelihood of late complications (including pericarditis, angina, myocardial infarction and accelerated atherosclerosis). Our clinical goals of this study are to: 1) Improve the accuracy of directing the radiation beam to the diseased myocardial tissue; 2) Reduce radiation toxicity to the surrounding healthy tissues of the heart, lungs and esophagus; and 3) Improve the overall NSCR treatment efficacy. These goals will be accomplished using novel radiation treatment processes, target definition, imaging, image guidance, target motion tracking and prediction, and radiation delivery gating methods. New MRI and cone beam CT (CBCT) image acquisition and reconstruction methods will be developed to characterize and compensate for cardiac and respiratory motion, and to dramatically improve target definition and motion management components of NSCR. New NSCR treatment processes will be developed to reduce the patient setup uncertainties on the treatment day, and to improve the radiation delivery accuracy by tracking the target motion and gating the radiation beam based on the real-time target position and the respiratory + ECG signals. The new treatment and imaging methods developed and tested under this study will be applicable to both MRI-guided radiation delivery systems (MR-Linacs) and CBCT image guided radiation delivery systems (CBCT-Linacs).