| 摘要: | 高強度聚焦超音波(High-Intensity Focused Ultrasound, HIFU)熱治療相較於傳統開放性手術，具有非侵入性、無輻射和出血量少等優點，其作用機制主要是以聲波聚焦時的機械效應和熱效應在生物體內產生高溫，使聚焦處的細胞發生凝固性的壞死。目前在前列腺癌、肝癌、乳癌、骨癌等，透過和靶向型微氣泡顯影劑的應用，能在早期偵測腫瘤並對其做熱治療和局部性較高濃度的藥物治療，然而若HIFU的聚焦不夠精準，會造成正常組織的傷害或目標腫瘤細胞燒灼不完全，而沒有達到治療應有的成效。
本研究藉由超音波影像定位出用來量測溫度的熱電偶尖點之位置，再以機械手臂控制HIFU換能器的聚焦點位置在HIFU聚焦軸向上移動並燒灼熱電偶尖點，其燒灼所得最高溫處視為HIFU聚焦點的真正位置，所得相對於機器人坐標系的最高溫位置和由超音波影像所算出的熱電偶尖點位置的差值即為原廠HIFU聚焦點位置規格的偏移量。聚焦點定位實驗為避開仿體的影響，先在水中燒灼單一熱電偶來測得最高溫位置和聚焦點偏移量，再以燒灼仿人體衰減係數的蛋白假體時產生的焦斑位置，來驗證定位實驗求得之偏移量，實驗結果顯示聚焦點偏移量達到6mm。接著本研究探討仿體形狀對於聚焦效果的影響等，其結果顯示仿體的對稱性有助於聲波聚焦的效率，最後在聚焦定位精準下，對豬的里肌肉或肥肉組織進行燒灼和對微氣泡顯影劑進行擊破，結果顯示燒灼單一種組織時可快速升溫，並使聚焦處的組織產生質變，而無論是附著在小區域, 矽膠管或海綿球型體的微氣泡顯影劑皆可輕易擊破。
;Compared with conventional open surgery, High-intensity focused ultrasound (HIFU) thermal therapy is non-invasive and has no radiation and less bleeding. The main mechanism of HIFU ablation treatment involves mechanical and thermal effects, which can generate high temperature to heat and destroy target cells. Currently, HIFU has been applied in the treatment of prostate, liver, breast, and bone tumor. With the application of targeting microbubbles, tumors can be treated by heat or local higher concentration of drug activated by HIFU. However, the focus point of HIFU must be located accurately and precisely so that it can destroy target tumor cells completely.
In this study, the focus point of a HIFU system is located. After the thermocouple tip for temperature measurement is located by ultrasound scan, a robot moves the HIFU focal point along the HIFU focusing axis to heat the thermocouple tip. The position with highest temperature is defined as the true position of the HIFU focal point. The difference between the true position of the HIFU focal point and that of the thermocouple tip detected by ultrasonic image and transferred relative to the robot coordinate system is the position offset of the focus point. The experimental results show the offset is 6mm.
This study also investigates the impact of phantom shape on the focusing effect. The experimental results show that the symmetry of the phantom body was helpful to the efficiency of the acoustic focusing. Finally, the calibrated HIFU system pork tissue is applied to ablate pork tissues (muscle and fat) and the targeting microbubbles, the results show that a single tissue can be quickly heated, but the heating of multiple-layer tissues are out of prediction, which requires further study. Moreover, HIFU targeting microbubbles can be detected and destroyed easily no matter they are targeting on small spots, silicon tubes or spherical sponges. |
