Developing computerized tools for cryosurgery planning

描述（由申请人提供）： 自1961年库珀和李发明了第一个冷冻探针以来，冷冻手术一直被认为是一种侵入性手术技术。20世纪90年代，焦耳-汤姆逊冷却（与加压气体突然释放相关的冷却效应）的新发展导致冷冻探针的尺寸急剧减小，并增加了可同时使用的冷冻探针的数量。在一次前列腺冷冻手术中同时操作十几个或更多个冷冻探针已经是常见的做法。如果有效地定位，使用大量微型冷冻探针的主要好处之一是对冷冻过程的上级控制。 目前，为特定手术选择冷冻探针的正确放置的过程是冷冻外科医生根据外科医生自己的经验和经验法则掌握的技术。冷冻探针通常以试错的方式操作，直到认为整个目标体积被冷冻。目前，还没有办法确定冷冻探针的最佳位置。次优冷冻探针定位可能使目标体积中的区域未被冷冻，可能导致健康周围组织的冷冻损伤，可能需要不必要的大量冷冻探针，可能增加外科手术的持续时间，并且可能增加冷冻手术后并发症的可能性，所有这些都会影响医疗的质量和成本。计算机化的规划工具将有助于减轻这些困难。 该研究小组最近提出了一种用于冷冻手术控制的新装置“冷冻加热器”。低温加热器是温度控制的电加热器。从广义上讲，低温加热器可以显着提高控制冷冻区域的形状和大小的能力，但是，为了实现低温加热器的全部好处，用于低温加热器定位的计算机化规划工具是必要的。 我们的目标是开发适用于所有可用冷却技术的冷冻手术计算机化规划工具。拟议的研究包括：（1）发展了一种有效的数值方法来模拟冷冻过程中的生物传热。（2）发展了一种基于力场模拟的有效的优化技术。(3)开发基于知识的优化技术。(4)规划工具的实验验证。 除了计划，所提出的工具的另一个重要应用是冷冻外科医生的培训。拟议的工具将提供冷冻外科医生的能力，可视化的冷冻过程的三维体积性质。 同样，它将允许外科医生探索冷冻探针和冷冻加热器的各种配置的性能，并观察每种配置可能导致的缺陷。这种可视化能力将为外科医生提供难以从物理实验或手术实践中获得的冷冻手术物理学的见解。

DESCRIPTION (provided by applicant): Cryosurgery has been known as an invasive surgical technique since 1961, when Cooper and Lee invented the first cryoprobe. In the 1990s, new developments in Joule-Thomson cooling (the cooling effect associated with a sudden relief of a pressurized gas) led to a dramatic decrease in the size of cryoprobes and an increase in the number of cryoprobes that could be used simultaneously. A dozen or more cryoprobes operating simultaneously in a single prostate cryosurgery is already common practice. If localized effectively, one of the primary benefits of using a large number of miniaturized cryoprobes is superior control over the freezing process. Currently, the process of selecting the correct placement of the cryoprobes for a specific procedure is an art held by the cryosurgeon, based on the surgeon's own experience and rules of thumb. Cryoprobes are typically operated in a trial-and-error fashion, until the entire target volume is thought to be frozen. Currently, there are no means to determine the optimal locations for the cryoprobes. Suboptimal cryoprobe localization may leave regions in the target volume unfrozen, may lead to cryoinjury of healthy surrounding tissues, may require an unnecessarily large number of cryoprobes, may increase the duration of the surgical procedure, and may increase the likelihood of post cryosurgery complications, all of which affect the quality and cost of the medical treatment. Computerized planning tools would help to alleviate these difficulties. The "cryoheater," a new device for cryosurgery control has recently been presented by the research team. The cryoheater is a temperature controlled electrical heater. In broad terms, cryoheaters can dramatically increase the ability to control the shape and size of the frozen region, however, to achieve the full benefits of cryoheaters, computerized planning tools for cryoheater localization are necessary. Our goal is to develop computerized planning tools for cryosurgery that are suitable for all available cooling techniques. The proposed research includes: (1) Development of an efficient numerical scheme for bioheat transfer simulations of cyroprocedures, (2) Development of an efficient optimization technique based on a force-field analogy. (3) Development of knowledge-based optimization techniques. (4) Experimental verification of the planning tool. Besides planning, another important application of the proposed tool is the training of cryosurgeons. The proposed tool will provide cryosurgeons with the ability to visualize the 3D volumetric nature of the freezing process. Likewise, it will allow the surgeon to explore the performance of various configurations of cryoprobes and cryoheaters, and observe the defects that would result from each. Such visualization capabilities will provide surgeons with insights into the physics of cryosurgery that are difficult to obtain from physical experiments or surgical practice.