Damianou C, Hynynen K
Arizona Cancer Center, University of Arizona Health Sciences Center, Tucson 85724.
Ultrasound Med Biol. 1993;19(9):777-87. doi: 10.1016/0301-5629(93)90094-5.
It has been proposed that high temperature short duration hyperthermia treatment would be perfusion insensitive and thus, significantly improved thermal exposure uniformity could be achieved. This study investigates the execution of such a treatment, which utilizes single spherically curved transducer and multiple sonications to cover the complete target volume. The spacing of neighboring pulses as a function of the transducer characteristics was studied utilizing computer simulations. In addition, the temperature elevation in front of the focal zone during multiple sonications was evaluated. It was found that significant delays (20 s or longer) between the sonications must be introduced in order to avoid unwanted tissue damage in front of the focal zone. In addition, decreasing the pulse duration and F-number reduced the temperature build-up in front of the focus. The results were verified in vivo in dog's thigh muscle. This study is important not only for hyperthermia but also for ultrasound surgery, and indicates that each sonication system must be carefully evaluated for potential thermal damage outside of the target volume prior to implementation in therapy.
有人提出，高温短时间热疗对灌注不敏感，因此可以显著提高热暴露均匀性。本研究探讨了这种治疗方法的实施，该方法利用单个球形弯曲换能器和多次超声处理来覆盖整个目标体积。利用计算机模拟研究了相邻脉冲间距与换能器特性的关系。此外，还评估了多次超声处理过程中焦区前方的温度升高情况。结果发现，必须在超声处理之间引入显著延迟（20秒或更长），以避免焦区前方不必要的组织损伤。此外，缩短脉冲持续时间和降低F数可减少焦点前方的温度积累。这些结果在犬大腿肌肉的体内实验中得到了验证。本研究不仅对热疗很重要，对超声手术也很重要，表明在治疗中实施之前，必须对每个超声处理系统在目标体积之外潜在的热损伤进行仔细评估。
