With focused ultrasound (FUS) gaining popularity as a therapeutic modality for brain diseases, the need for skull phantoms that are suitable for evaluating FUS protocols is increasing. In the current study, the acoustical properties of several three-dimensional (3D) printed thermoplastic samples were evaluated to assess their suitability to mimic human skull and bone accurately. Samples were 3D printed using eight commercially available thermoplastic materials. The acoustic properties of the printed samples, including attenuation coefficient, speed of sound, and acoustic impedance, were investigated using transmission-through and pulse-echo techniques. The ultrasonic attenuation, estimated at a frequency of 1.1 MHz, varied from approximately 7 to 32 dB/cm. The frequency dependence of attenuation was described by a power law in the frequency range of 0.2–3.5 MHz, and the exponential index of frequency was found to vary from 1.30 to 2.24. The longitudinal velocity of 2.7 MHz sound waves was in the range of 1700–3050 m/s. The results demonstrate that thermoplastics could potentially be used for the 3D construction of high-quality skull phantoms.

中文翻译：

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3D打印热塑性塑料的声学特性

随着聚焦超声（FUS）作为用于脑部疾病的治疗手段而日益普及，对适用于评估FUS协议的颅骨体模的需求正在增加。在当前的研究中，评估了几个三维（3D）打印的热塑性塑料样品的声学特性，以评估其精确模拟人的头骨和骨骼的适用性。使用八种可商购的热塑性材料对样品进行3D打印。使用透射和脉冲回波技术研究了印刷样品的声学特性，包括衰减系数，声速和声阻抗。估计在1.1 MHz频率下的超声衰减范围大约为7至32 dB / cm。幂律描述了在0.2-3.5 MHz频率范围内衰减的频率依赖性，发现频率的指数在1.30到2.24之间变化。2.7 MHz声波的纵向速度在1700–3050 m / s的范围内。结果表明，热塑性塑料可以潜在地用于高质量头骨模型的3D构造。