Slezak Cyrill, Flatscher Jonas, Slezak Paul
Department of Physics, Utah Valley University, Orem, UT 84058, USA.
Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, 1200 Vienna, Austria.
Biomedicines. 2022 Jun 20;10(6):1457. doi: 10.3390/biomedicines10061457.
The potential beneficial regenerative and stimulatory extracorporeal shock wave therapy (ESWT) applications to the central nervous system have garnered interest in recent years. Treatment zones for these indications are acoustically shielded by bones, which heavily impact generated sound fields. We present the results of high-resolution tissue-realistic simulations, comparing the viability of different ESWT applicators in their use for transcranial applications. The performances of electrohydraulic, electromagnetic, and piezoelectric transducers for key reflector geometries are compared. Based on density information obtained from CT imaging of the head, we utilized the non-linear wave propagation toolset Matlab k-Wave to obtain spatial therapeutic sound field geometries and waveforms. In order to understand the reliability of results on the appropriate modeling of the skull, three different bone attenuation models were compared. We find that all currently clinically ESWT applicator technologies show significant retention of peak pressures and energies past the bone barrier. Electromagnetic transducers maintain a significantly higher energy flux density compared to other technologies while low focusing strength piezoelectric applicators have the weakest transmissions. Attenuation estimates provide insights into sound field degradation and energy losses, indicating that effective transcranial therapies can readily be attained with current applicators. Furthermore, the presented approach will allow for future targeted in silico development and the design of applicators and therapy plans to ultimately improve therapeutic outcomes.
近年来，体外冲击波疗法（ESWT）对中枢神经系统潜在的有益再生和刺激作用已引起关注。这些适应症的治疗区域被骨骼声学屏蔽，这对产生的声场有很大影响。我们展示了高分辨率组织逼真模拟的结果，比较了不同ESWT施波器用于经颅应用的可行性。比较了关键反射器几何形状的电动液压、电磁和压电换能器的性能。基于从头部CT成像获得的密度信息，我们利用非线性波传播工具集Matlab k-Wave来获得空间治疗声场几何形状和波形。为了了解颅骨适当建模结果的可靠性，比较了三种不同的骨衰减模型。我们发现，目前所有临床ESWT施波器技术在穿过骨屏障后都显示出峰值压力和能量的显著保留。与其他技术相比，电磁换能器保持着显著更高的能量通量密度，而低聚焦强度的压电施波器传输最弱。衰减估计提供了对声场退化和能量损失的见解，表明使用当前的施波器可以很容易地实现有效的经颅治疗。此外，所提出的方法将允许未来有针对性的计算机模拟开发以及施波器和治疗计划的设计，以最终改善治疗效果。
