Reeves J, Birch M, Munro K, Collier R
Clinical Physics Department, Royal London Hospital, UK.
Phys Med Biol. 2002 Oct 7;47(19):3557-64. doi: 10.1088/0031-9155/47/19/309.
A set of helical microwave antennas was designed to investigate their potential use in thermal therapy of Barrett's oesophagus. The antennas had a diameter of up to 3.3 mm and various lengths between 20 and 37 mm; these were designed to operate at 915 MHz. Sets of polytetrafluoroethylene (PTFE) formers were constructed to improve the repeatability and reproducibility of the helix manufacture. Small diameter copper wire was wound over the formers and connected to the coaxial cable at the inner and outer conductor junctions. The power deposition profiles of the antennas were measured in a muscle-equivalent phantom using an infrared camera. The effects of antenna length and coil spacing were characterized. It was observed that uniform temperature profiles along the antenna length were achieved with a length of wire of 99 mm +/- 2 mm. The effective heating length (length of the antenna that exhibits > 50% of the maximum temperature rise) was comparable to the antenna length. The radial penetration depth of 50% of the antenna surface temperature for the optimum 20 mm antenna was 2.5 mm from the antenna outer surface.
设计了一组螺旋形微波天线，以研究其在巴雷特食管热疗中的潜在用途。这些天线直径达3.3毫米，长度在20至37毫米之间不等；设计它们在915兆赫兹频率下工作。制作了多组聚四氟乙烯（PTFE）成型器，以提高螺旋制造的可重复性和再现性。将小直径铜线缠绕在成型器上，并在内导体和外导体连接处连接到同轴电缆。使用红外摄像机在肌肉等效体模中测量天线的功率沉积分布。对天线长度和线圈间距的影响进行了表征。观察到，使用长度为99毫米±2毫米的导线可沿天线长度实现均匀的温度分布。有效加热长度（呈现最大温度上升>50%的天线长度）与天线长度相当。对于最佳的20毫米天线，天线表面温度50%处的径向穿透深度距离天线外表面为2.5毫米。
