Tu S J, Hynynen K, Roemer R B
Department of Radiation Oncology, Arizona Cancer Center, University of Arizona, Arizona Health Science Center, Tucson 85724.
Int J Hyperthermia. 1994 Sep-Oct;10(5):707-22. doi: 10.3109/02656739409022449.
The temperature distributions produced in neck tumours by using either a single, scanned transducer (a unidirectional scan) or two separate transducers whose axis are perpendicular (a bidirectional scan) were simulated. The three-dimensional neck model included separate anatomical regions for the normal neck muscle tissue, the tumour, the spinal column and the trachea (no large blood vessels). The effects of variations in the transducer frequency and f number, the tumour size and location, and the normal and tumour blood perfusion rates were studies. The best simulated temperature distributions were produced by bidirectionally scanned, 2 MHz, f number 2.0 ultrasound transducers whose powers were modulated as a function of position. The simulated temperature distributions from such modulated bidirectional scans were significantly better than those of both unidirectional and unmodulated bidirectional scans. The 1-MHz transducers generally produced hot spots at the tissue-spine and/or tissue-trachea interface. The 3-MHz transducers eliminated those deep hot spots but created other hot spots close to the skin surface, and did not adequately heat the deeper regions of the tumour. These results from the simplified computer simulations may be used to guide the construction of improved ultrasound hyperthermia systems for the treatment of neck tumours.
利用单个扫描换能器（单向扫描）或两个轴相互垂直的独立换能器（双向扫描）在颈部肿瘤中产生的温度分布进行了模拟。三维颈部模型包括正常颈部肌肉组织、肿瘤、脊柱和气管（无大血管）的独立解剖区域。研究了换能器频率和f数、肿瘤大小和位置以及正常和肿瘤血液灌注率变化的影响。最佳模拟温度分布由双向扫描的2MHz、f数为2.0的超声换能器产生，其功率根据位置进行调制。这种调制双向扫描的模拟温度分布明显优于单向和未调制双向扫描。1MHz换能器通常在组织-脊柱和/或组织-气管界面产生热点。3MHz换能器消除了那些深部热点，但在靠近皮肤表面处产生了其他热点，并且没有充分加热肿瘤的深部区域。这些简化计算机模拟的结果可用于指导构建用于治疗颈部肿瘤的改进型超声热疗系统。
