Adaptive Mechanical Models for Realistic Radiation Sterilization Simulations

项目摘要 医疗器械开发具有在开发周期早期降低风险的基本模式。 开发人员正在使用有限元分析等计算工具来减轻热负荷带来的风险， 机械应力等。该范例有一个例外：灭菌确认。 灭菌确认在开发周期后期进行，因为需要实际的物理器械， 开展这些活动。灭菌配置（例如，包装设计、辐射束方向等）是 反复修改，直到满足法规要求。这种“试错法”的做法很普遍 消毒的各个方面。作为另一个例子，当在灭菌方式之间进行选择时， 医疗设备公司通常依赖于经验法则，这可能导致他们的设备的次优选择。 然而，使用模拟来模拟辐射灭菌过程是一个新兴领域， 承诺在开发过程的早期解决灭菌确认问题，从而允许设计 灭菌方法。这意味着一旦设备的计算机辅助设计（CAD）模型存在， 可进行模拟以分析器械是否将通过灭菌确认或缓解措施是否将 需要设置 虽然模拟是在设计过程早期解决灭菌问题的关键因素，但我们发现， 设备的代表性可能不足以讲述整个故事。无菌包装是另一个 需要考虑的重要因素。该包确定如何将设备呈现给 辐射束，但在封装内，该设备可以在一定程度上移动， 设备也可以彼此相对移动。因此，存在一系列可能的取向和位置， 影响器械将接受的总体辐射剂量的器械。 在这个项目中，我们建议开发一个软件工具，可以生成一个家庭的CAD模型，跨越 包装限制和器械预期的器械方向和位置的实际范围 配置.该工具将考虑重力和其他力，以真实地描述可能的 配置. 我们还将开发一种自定义体模，可用于模拟和测量，以探索 剂量范围。测量剂量和模拟剂量的比较研究将用于总体 验证我们的方法。 在该项目下开发的新工具将提高辐射灭菌模拟的实用性， 灭菌设计的路径。

Project Summary Medical Device development has an underlying paradigm to reduce risk early in the development cycle. Developers are using computational tools such as finite element analysis to mitigate risks from thermal loads, mechanical stresses etc. There is one exception to this paradigm: sterilization validation. Sterilization validation is addressed late in the development cycle as an actual physical device is needed to perform these activities. Sterilization configurations (e.g., packaging design, radiation beam direction, etc.) are iteratively modified until the regulatory requirements are met. This “trial-and-error” approach is prevalent throughout all aspects of sterilization. As another example, when choosing between sterilization modalities, medical device companies often rely on rules-of-thumb which may lead to a suboptimal choice for their device. However, use of simulations to model the radiation sterilization process is an emerging field that has the promise to address sterilization validation early in the development process and thereby allow for a Design for Sterilization approach. That means as soon as a Computer Aided Design (CAD) model of the device exists, simulation can be performed to analyze whether the device will pass sterilization validation or mitigations will be needed. While simulations are a key ingredient to address sterilization early in the design process, we find that a single representation of the device might not be sufficient to tell the whole story. Sterile packaging is another important factor that needs to be considered. The package determines how the device is presented to the radiation beam, but within the package the device can move to a certain degree with separate parts of the device also can move against each other. Thus, there is a range of possible orientations and positions of the device that will influence the overall radiation dose that the device will receive. In this project we propose to develop a software tool that can generate a family of CAD models that spans the realistic range of device orientations and positions expected from packaging constraints and device configuration. The tool will account for gravity and other forces to realistically describe the range of possible configurations. We also will develop a custom phantom that can be used in simulations and in measurements to explore the range of dose received. The comparative study of measured and simulated dose will be used to overall validate our approach. The new tool developed under this project will improve the utility of radiation sterilization simulations and pave the path for Design for Sterilization.