Waterman F M, Tupchong L, Matthews J, Nerlinger R
Department of Radiation Oncology and Nuclear Medicine, Thomas Jefferson University Hospital, Philadelphia, PA 19017.
Int J Radiat Oncol Biol Phys. 1989 Nov;17(5):1049-55. doi: 10.1016/0360-3016(89)90154-5.
Mechanisms of heat removal were studied in five recurrent squamous cell head or neck carcinomas, 50-150 cm3, heated by use of external 915 MHz microwave applicators. Thermal clearance measurements were made at a single point in each tumor. Three profiles of the tissue temperature were also measured in orthogonal directions about this point. The conduction term of the bioheat equation was evaluated from the orthogonal temperature profiles by the method of finite differences. The perfusion term of the bioheat equation was determined from the rate of temperature decay corrected for conduction. The results show that thermal conduction plays a major role in the dissipation of thermal energy during local hyperthermia. The rate of removal thermal energy by conduction ranged between 20 and 150 percent of that by perfusion. The temperature profiles show that conduction is higher than is generally expected due to heterogeneities in the blood flow which produce rapid changes in the temperature gradient. The results of this study demonstrate that the heat transport by thermal conduction in perfused tissue cannot be assumed to be small, or negligible, in comparison to that by perfusion.
在5例复发性头颈部鳞状细胞癌中研究了散热机制，肿瘤体积为50 - 150立方厘米，使用外部915兆赫微波施加器进行加热。在每个肿瘤的单个点进行热清除测量。还在围绕该点的正交方向上测量了三个组织温度剖面。通过有限差分法从正交温度剖面评估生物热方程的传导项。生物热方程的灌注项由校正传导后的温度衰减率确定。结果表明，热传导在局部热疗期间热能的消散中起主要作用。通过传导去除热能的速率为通过灌注去除热能速率的20%至150%。温度剖面表明，由于血流中的异质性导致温度梯度快速变化，传导高于一般预期。本研究结果表明，与灌注相比，灌注组织中热传导的热传递不能被认为是小的或可忽略的。
