Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada.
Department of Medical Physics, BC Cancer, Vancouver, British Columbia V5Z 4E6, Canada.
Biomed Phys Eng Express. 2024 Feb 29;10(2). doi: 10.1088/2057-1976/ad29a4.
Cardiac radiosurgery is a non-invasive treatment modality for ventricular tachycardia, where a linear accelerator is used to irradiate the arrhythmogenic region within the heart. In this work, cardiac magnetic resonance (CMR) cine images were used to quantify left ventricle (LV) segment-specific motion during the cardiac cycle and to assess potential advantages of cardiac-gated radiosurgery.CMR breath-hold cine images and LV contour points were analyzed for 50 controls and 50 heart failure patients with reduced ejection fraction (HFrEF, EF < 40%). Contour points were divided into anatomic segments according to the 17-segment model, and each segment was treated as a hypothetical treatment target. The optimum treatment window (one fifth of the cardiac cycle) was determined where segment centroid motion was minimal, then the maximum centroid displacement and treatment area were determined for the full cardiac cycle and for the treatment window. Mean centroid displacement and treatment area reductions with cardiac gating were determined for each of the 17 segments.Full motion segment centroid displacements ranged between 6-14 mm (controls) and 4-11 mm (HFrEF). Full motion treatment areas ranged between 129-715 mm(controls) and 149-766 mm(HFrEF). With gating, centroid displacements were reduced to 1 mm (controls and HFrEF), while treatment areas were reduced to 62-349 mm(controls) and 83-393 mm(HFrEF). Relative treatment area reduction ranged between 38%-53% (controls) and 26%-48% (HFrEF).This data demonstrates that cardiac cycle motion is an important component of overall target motion and varies depending on the anatomic cardiac segment. Accounting for cardiac cycle motion, through cardiac gating, has the potential to significantly reduce treatment volumes for cardiac radiosurgery.
心脏放射外科手术是一种治疗室性心动过速的非侵入性治疗方法，它使用线性加速器来照射心脏内的心律失常区域。在这项工作中，心脏磁共振（CMR）电影图像被用于量化心动周期中心脏的左心室（LV）节段特异性运动，并评估心脏门控放射外科手术的潜在优势。对 50 名对照者和 50 名射血分数降低（EF < 40%）的心力衰竭患者的 CMR 屏气电影图像和 LV 轮廓点进行了分析。轮廓点根据 17 节段模型分为解剖节段，每个节段都被视为一个假设的治疗目标。确定了节段质心运动最小的最佳治疗窗口（心脏周期的五分之一），然后确定了整个心脏周期和治疗窗口的最大质心位移和治疗面积。确定了 17 个节段中每个节段的心脏门控后平均质心位移和治疗面积减少。全运动节段质心位移范围为 6-14mm（对照）和 4-11mm（HFrEF）。全运动治疗面积范围为 129-715mm（对照）和 149-766mm（HFrEF）。使用门控时，质心位移减少到 1mm（对照和 HFrEF），而治疗面积减少到 62-349mm（对照）和 83-393mm（HFrEF）。相对治疗面积减少范围为 38%-53%（对照）和 26%-48%（HFrEF）。这些数据表明，心动周期运动是整体目标运动的一个重要组成部分，并且根据心脏的解剖节段而有所不同。通过心脏门控考虑心动周期运动有可能显著减少心脏放射外科手术的治疗体积。
