Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Via Ospedale 12, 6500, Bellinzona, Switzerland.
Department of Mechanical and Aerospace Engineering, "Sapienza" University of Rome, Rome, Italy.
Endocrine. 2018 Mar;59(3):506-509. doi: 10.1007/s12020-017-1350-1. Epub 2017 Jun 21.
The non-surgical therapies of benign thyroid nodules are gaining momentum due to the possibility to reduce the nodule's volume and avoid surgery. As the last technique introduced, high intensity focused ultrasound allows the thermal tissue treatment by directing energy inside the targeted nodule with no invasive instruments. In the present study we applied the Food and Drug Administration high intensity focused ultrasound simulator to in-silico phantom to evaluate the effects obtained by different acoustic powers.
The simulated layers were water and thyroid tissue. The source was a spherically curved circular transducer with radius r = 2.3 cm generating a continuous wave beam at a frequency of 3 MHz. The focal distance was 6.5 cm. The sequence included a pulse (8 s) with acoustic power at different value from 5 to 50 W, and a cooling-off interval (32 s).
The use of acoustic power of 5 W allowed to achieve the threshold of temperature for coagulative necrosis (55 °C) at 1 s. The simulation with 50 W showed that temperature was significantly higher (above 300 °C) at 1 s and is maintained at high levels for a long interval.
Since 2016, we treated patients according to the present experience, and a significant reduction of nodule's volume was observed with good patent's comfort and no complications (unpublished data). Also, no anesthesia was practiced. We feel that the present data could contribute to develop a high intensity focused ultrasound therapy of benign thyroid nodules free from potential complications.
由于有可能缩小结节体积并避免手术，良性甲状腺结节的非手术治疗方法正受到越来越多的关注。高强度聚焦超声作为最后引入的技术，通过将能量引导至目标结节内部，无需使用侵入性仪器即可实现组织热疗。在本研究中，我们应用食品和药物管理局的高强度聚焦超声模拟器对计算机模拟的体模进行评估，以研究不同声功率所获得的效果。
模拟层为水和甲状腺组织。声源为半径 r=2.3cm 的球形弯曲圆形换能器，在 3MHz 频率下产生连续波束。焦域距离为 6.5cm。序列包括一个在不同声功率（5-50W）下持续 8s 的脉冲和一个冷却间隔（32s）。
使用 5W 的声功率可以在 1s 时达到凝固性坏死的温度阈值（55°C）。50W 的模拟显示，1s 时温度显著升高（超过 300°C），并在较长时间内保持在较高水平。
自 2016 年以来，我们根据目前的经验对患者进行了治疗，观察到结节体积显著缩小，患者舒适度良好，且无并发症（未发表数据）。此外，我们未进行麻醉。我们认为目前的数据有助于开发出一种无潜在并发症的良性甲状腺结节高强度聚焦超声治疗方法。
