Myerson R J, Leybovich L, Emami B, Grigsby P W, Straube W, Von Gerichten D
Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri.
Int J Hyperthermia. 1991 Nov-Dec;7(6):937-51. doi: 10.3109/02656739109056460.
The BSD 2000 system is an array of microwave antennas operating in the 60-120 MHz range. It is a four-quadrant regional hyperthermia device with phase control permitting the operator to choose the point of constructive interference. A computer preplanning system is provided. We have compared the computer predictions with measured relative specific absorption rate (SAR) distributions in muscle equivalent phantoms and pig cadaver. The predicted SAR distribution is in qualitative agreement with observation, although differences of approximately 3-5 cm in the location of iso- SAR contours were noted. The longitudinal dependence of relative of distance cephalad to the central plane of the power distribution was measured, and it was found that a length of 15-20 cm was covered by the 50% iso-SAR. SAR measurements in the spinal canal of a pig cadaver showed that, even at resonance frequency, the measured SAR in the cervical spine was small (0.07 of central axis SAR). However, the spinal canal SAR as measured in the central plane of an evenly balanced configuration was 0.6 of the peak SAR. Marked reduction of the spinal canal SAR could be obtained with steering techniques and was in good agreement with the computer preplan. This paper reviews preliminary clinical experience with 17 patients. All but 2 patients were treated with steering techniques to permit partial sparing of normal tissues. The goal of maintaining central tumour temperature at or above 42 degrees C for at least 30 min was maintained in 41 of 67 sessions (61%) and in at least one session for all but 2 patients. Seventy-seven per cent of monitored tumor points attained at least 42 degrees C in patients for whom thermal mapping was performed. Significant cardiovascular stress developed during hyperthermia in two patients. There have been five complete responses and seven partial responses in the 17 patients.
BSD 2000系统是一组工作在60 - 120兆赫兹频段的微波天线。它是一种四象限区域热疗设备，具备相位控制功能，可让操作人员选择相长干涉点。该系统还配备了计算机预规划系统。我们已将计算机预测结果与在肌肉等效体模和猪尸体中测得的相对比吸收率（SAR）分布进行了比较。预测的SAR分布与观察结果在定性上相符，不过在等SAR轮廓位置上发现了约3 - 5厘米的差异。测量了相对于功率分布中心平面头侧距离的相对纵向依赖性，发现50%等SAR覆盖的长度为15 - 20厘米。在猪尸体椎管内进行的SAR测量表明，即使在共振频率下，颈椎处测得的SAR也很小（为中心轴SAR的0.07）。然而，在均匀平衡配置的中心平面测得的椎管SAR为峰值SAR的0.6。采用转向技术可显著降低椎管SAR，且与计算机预规划结果高度吻合。本文回顾了17例患者的初步临床经验。除2例患者外，所有患者均采用转向技术治疗，以部分保留正常组织。在67个疗程中的41个（61%）中实现了将中心肿瘤温度维持在42摄氏度或以上至少30分钟的目标，除2例患者外，所有患者至少有一个疗程达到该目标。在进行热图绘制的患者中，77%的监测肿瘤点达到了至少42摄氏度。两名患者在热疗过程中出现了明显的心血管应激反应。17例患者中有5例完全缓解，7例部分缓解。
