Lung David C, Stahovich Thomas F, Rabin Yoed
Department of Mechanical Engineering, Carnegie Mellon University, 15213 Pittsburgh, PA, USA.
Comput Methods Biomech Biomed Engin. 2004 Apr;7(2):101-10. doi: 10.1080/10255840410001689376.
Cryosurgery is the destruction of undesired biological tissues by freezing. For internal organs, multiple cryoprobes are inserted into the tissue with the goal of maximizing cryoinjury within a predefined target region, while minimizing cryoinjury to the surrounding tissues. The objective of this study is to develop a computerized planning tool to determine the best locations to insert the cryoprobes, based on bioheat transfer simulations. This tool is general and suitable for all available cooling techniques and hardware. The planning procedure employs a novel iterative optimization technique based on a force-field analogy. In each iteration, a single transient bioheat transfer simulation of the cryoprocedure is computed. At the end of the simulation, regions of tissue that would have undesired temperatures apply "forces" to the cryoprobes directly moving them to better locations. This method is more efficient than traditional numerical optimization techniques, because it requires significantly fewer bioheat transfer simulations for each iteration of planning. For demonstration purposes, 2D examples on cross sections typical of prostate cryosurgery are given.
冷冻手术是通过冷冻来破坏不需要的生物组织。对于内部器官,将多个冷冻探针插入组织中,目的是在预定义的目标区域内使冷冻损伤最大化,同时将对周围组织的冷冻损伤最小化。本研究的目的是基于生物热传递模拟开发一种计算机化规划工具,以确定插入冷冻探针的最佳位置。该工具具有通用性,适用于所有可用的冷却技术和硬件。规划过程采用了一种基于力场类比的新型迭代优化技术。在每次迭代中,计算一次冷冻手术的单个瞬态生物热传递模拟。在模拟结束时,温度不理想的组织区域会对冷冻探针施加“力”,直接将它们移动到更好的位置。这种方法比传统的数值优化技术更有效,因为在每次规划迭代中,它所需的生物热传递模拟要少得多。为了演示目的,给出了前列腺冷冻手术典型横截面的二维示例。