Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
Int J Hyperthermia. 2010;26(4):376-88. doi: 10.3109/02656730903521383.
Motivation for this research was a patient with large and bulky melanoma lesions on a leg, treated with hyperthermia in a special set-up with an open water bolus and two opposing applicators. Treatment planning was used to find the most suitable heating method, comparing 70 MHz capacitive contact flexible microstrip applicators (CFMAs) and 70 MHz waveguides.
The first three sessions were performed with CFMA applicators; the last session with waveguides. Power and water temperature were adjusted to achieve clinically relevant temperatures. Finite difference time domain (FDTD) simulations were performed for a CFMA and waveguide on a fat-muscle geometry to compare effective field size (EFS) and effective heating depth (EHD). A CT scan of the patient's leg was automatically segmented into muscle, fat and bone; tumour lesions were outlined manually. Patient simulations were performed to evaluate the 3D heating pattern and to compare CFMAs and waveguides for equal power and water temperature.
Hyperthermia treatment was well tolerated. Temperature measurements indicated mainly superficial heating with CFMAs. Simulated EHD was 2.1 and 2.4 cm for CFMA and waveguide, respectively and EFS was 19.6 x 16.2 cm(2) and 19.4 x 16.3 cm(2). Simulation results confirmed the better performance of the waveguides. For normal amounts of fat tissue, approximately twice as much power is absorbed in fat with CFMAs compared to waveguides. [corrected] Simulations showed that a relatively high water temperature ( approximately 42 degrees C) improves the overall temperature distribution.
CFMAs and waveguides have a similar EFS and EHD, but for large extremity lesions, the performance of 70 MHz waveguides is favourable compared to 70 MHz CFMA applicators.
本研究的动机是一名腿部有大面积黑色素瘤病变的患者，采用带有开放式水囊和两个相对应用器的特殊设备进行了热疗。治疗计划用于寻找最合适的加热方法，比较了 70MHz 电容接触式柔性微带天线（CFMA）和 70MHz 波导。
前三个疗程使用 CFMA 应用器进行治疗；最后一个疗程使用波导。调整功率和水温以达到临床相关温度。对脂肪-肌肉几何形状上的 CFMA 和波导进行了有限差分时域（FDTD）模拟，以比较有效场大小（EFS）和有效加热深度（EHD）。患者腿部的 CT 扫描自动分为肌肉、脂肪和骨骼；肿瘤病变手动勾勒。进行了患者模拟，以评估 3D 加热模式，并比较 CFMA 和波导在相同功率和水温下的性能。
热疗耐受性良好。温度测量表明 CFMA 主要进行表面加热。模拟 EHD 分别为 2.1cm 和 2.4cm，EFS 分别为 19.6x16.2cm(2)和 19.4x16.3cm(2)。模拟结果证实了波导的更好性能。对于正常量的脂肪组织，与波导相比，CFMA 吸收的脂肪中的功率约高两倍。模拟表明，相对较高的水温（约 42 摄氏度）可改善整体温度分布。
CFMA 和波导具有相似的 EFS 和 EHD，但对于大的肢体病变，70MHz 波导的性能优于 70MHz CFMA 应用器。
