Use of Controlled Acoustic Cavitation to Enhance and Monitor Treatment by High-Intensity Focussed Ultrasound (HIFU)

高强度聚焦超声（HIFU）正在成为一种有前途的技术，用于非侵入性治疗深部肿瘤（即无需手术）。在体外产生的聚焦超声波可以在其焦点处产生足够的组织加热，从而导致细胞死亡，使超声传播路径中的其他组织不受影响。然而，在目前的状态下，使用这种技术摧毁相对较大的肿瘤所需的时间相当长。此外，在HIFU暴露期间监测被消融的组织区域是极其困难的，这进一步阻碍了治疗功效并阻止了其广泛的临床应用。最近的研究表明，在适当的条件下，高强度超声波可以在焦点处产生并激发微米级的气泡，这大大增加了HIFU治疗期间的加热速率。这些微泡可以在HIFU暴露期间容易地检测到。拟议的研究主要旨在开发一种控制器，该控制器将在整个HIFU暴露过程中在焦点处产生和维持微泡，防止它们不受控制地向HIFU换能器生长。如果能够证明组织仅在检测到微泡的区域中被破坏，则将有可能真实的监测HIFU治疗，同时还实现更快的加热速率。这将促进HIFU治疗的临床应用，从而改善全球癌症患者的生活质量。

High-Intensity Focused Ultrasound (HIFU) is emerging as a promising technique for treating deep-seated tumours non-invasively (i.e. without surgery). A focused ultrasound wave generated outside the body can produce sufficient tissue heating at its focus to cause cell death, leaving tissue elsewhere in the ultrasound propagation path unaffected. However, the time that it takes to destroy relatively large tumors using this technique in its present state is rather long. In addition, it is extremely difficult to monitor the region of tissue being ablated during HIFU exposure, which further hinders the treatment efficacy and prevents its widespread clinical uptake. Recent research has shown that, under the right conditions, the high-intensity ultrasound wave can generate and excite micron-sized bubbles at the focus, which substantially increases the rate of heating during HIFU treatment. These microbubbles can be readily detected during HIFU exposure. The proposed research aims primarily at developing a controller that will produce and sustain microbubbles at the focus throughout HIFU exposure, preventing them from growing uncontrollably toward the HIFU transducer. If it can be shown that tissue is only destroyed in the region where microbubbles are detected, then it will become possible to monitor HIFU treatment in real time, whilst also achieving faster rates of heating. This should promote clinical uptake of HIFU therapy, thus improving the quality of life of cancer patients worldwide.