Clement Greg T, Hynynen Kullervo
Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2002 Apr;49(4):447-53. doi: 10.1109/58.996562.
A new method for focusing ultrasound energy in brain tissue through the skull is investigated. The procedure is designed for use with a therapeutic transducer array and a small catheter-inserted hydrophone receiver placed in the brain to guide the array's focus. When performed at high-intensity, a focal intensity on the order of several hundred watts per centimeter-squared is achieved, and cells within a target volume are destroyed. The present study tests the feasibility and range of the method using an ex vivo human skull. Acoustic phase information is obtained from the stationary receiver and used to electrically shift the beam to new locations as well as correct for aberrations due to the skull. The method is applied to a 104-element 1.1 MHz array and a 120-element 0.81 MHz array. Using these array configurations, it is determined that the method can reconstruct and steer a focus over a distance of 50 mm. Application of this minimally invasive technique for ultrasound brain therapy and surgery also is investigated in vitro with a 64-element 0.664 MHz hemisphere array designed for transskull surgery. Tissue is placed inside of a skull and a catheter-inserted receiver is inserted into the tissue. A focus intense enough to coagulate the tissue is achieved at a predetermined location 10 mm from the receiver, the maximum distance that this large element array can electronically steer the focus.
研究了一种通过颅骨在脑组织中聚焦超声能量的新方法。该程序设计用于与治疗性换能器阵列以及置于脑内的小型插入导管的水听器接收器配合使用，以引导阵列的聚焦。当以高强度执行时，可实现每平方厘米数百瓦量级的聚焦强度，并破坏目标体积内的细胞。本研究使用离体人类颅骨测试该方法的可行性和范围。从固定接收器获取声相位信息，并用于将波束电移至新位置以及校正由于颅骨引起的像差。该方法应用于104阵元1.1MHz阵列和120阵元0.81MHz阵列。使用这些阵列配置，确定该方法可以在50mm的距离上重建并控制焦点。还使用专为经颅手术设计的64阵元0.664MHz半球阵列在体外研究了这种微创超声脑治疗和手术技术的应用。将组织置于颅骨内，并将插入导管的接收器插入组织中。在距接收器10mm的预定位置实现了足以使组织凝固的焦点，这是这种大型阵元阵列能够以电子方式控制焦点的最大距离。
