Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA.
Sandia National Laboratories, Albuquerque, NM, USA.
Int J Hyperthermia. 2021;38(1):679-690. doi: 10.1080/02656736.2021.1914872.
Magnetic resonance guided focused ultrasound (MRgFUS) treatment of tumors uses inter-sonication delays to allow heat to dissipate from the skin and other near-field tissues. Despite inter-sonication delays, treatment of tumors close to the skin risks skin burns. This work has designed and evaluated an open-source, conformable, skin-cooling system for body MRgFUS treatments to reduce skin burns and enable ablation closer to the skin.
A MR-compatible skin cooling system is described that features a conformable skin-cooling pad assembly with feedback control allowing continuous flow and pressure maintenance during the procedure. System performance was evaluated with hydrophone, phantom and porcine studies. Sonications were performed 10 and 5 mm from the skin surface under both control and forced convective skin-cooling conditions. 3D MR temperature imaging was acquired in real time and the accumulated thermal dose volume was measured. Gross analysis of the skin post-sonication was further performed. Device conformability was demonstrated at several body locations.
Hydrophone studies demonstrated no beam aberration, but a 5-12% reduction of the peak pressure due to the presence of the skin-cooling pad assembly in the acoustic near field. Phantom evaluation demonstrated there is no MR temperature imaging precision reduction or any other artifacts present due to the coolant flow during MRgFUS sonication. The porcine studies demonstrated skin burns were reduced in size or eliminated when compared to the control condition.
An open-source design of an MRgFUS active skin cooling system demonstrates device conformability with a reduction of skin burns while ablating superficial tissues.
磁共振引导聚焦超声（MRgFUS）治疗肿瘤利用 inter-sonication 延迟来允许热量从皮肤和其他近场组织消散。尽管存在 inter-sonication 延迟，但靠近皮肤治疗肿瘤存在皮肤灼伤的风险。本工作设计并评估了一种开源、顺应性的皮肤冷却系统，用于身体 MRgFUS 治疗，以减少皮肤灼伤并实现更接近皮肤的消融。
描述了一种兼容磁共振的皮肤冷却系统，其特点是具有顺应性皮肤冷却垫组件和反馈控制，允许在程序过程中连续流动和压力维持。使用水听器、体模和猪研究对系统性能进行了评估。在控制和强制对流皮肤冷却条件下，从皮肤表面 10 和 5mm 处进行了声处理。实时采集 3D MR 温度成像，并测量累积热剂量体积。进一步对超声处理后的皮肤进行了宏观分析。在几个身体部位展示了设备的顺应性。
水听器研究表明，由于声近场中存在皮肤冷却垫组件，没有波束失真，但峰值压力降低了 5-12%。体模评估表明，由于在 MRgFUS 声处理期间冷却液流动，不存在 MR 温度成像精度降低或任何其他伪影。猪研究表明，与对照条件相比，皮肤灼伤的大小减小或消除。
一种开源的 MRgFUS 主动皮肤冷却系统设计证明了设备的顺应性，可以减少皮肤灼伤，同时消融表面组织。
