This paper presents a two magnetic sensor based tracking method for a magnetically inflated intragastric balloon capsule (MIBC) which is used for obesity treatment. After the MIBC is swallowed, it is designed to be inflated inside the stomach by approaching a permanent magnet (PM) externally near the abdomen. However, if the balloon inflation is accidentally triggered while the MIBC is still in the esophagus, the esophagus will be damaged. Therefore, to safely inflate the MIBC, we aim to track the MIBC’s position along the esophagus and confirm the MIBC passes through. Typically, magnetic sensor based tracking systems tend to be bulky and costly since they involve computationally intensive optimization with many magnetic sensors. To solve those problems, we develop an algorithm that estimates the position of the PM inside the MIBC by using the grid search combined with the dynamically confined search range and search threshold modulation. Our tracking method achieved an average 1D position error of 3.48 mm which is comparable to the up to 4 mm average error for the other magnetic sensor based tracking systems that require more sensors and computational power compared to our system.

本文提出了一种基于两个磁传感器的磁膨胀胃内球囊胶囊 (MIBC) 的跟踪方法，该胶囊用于肥胖治疗。在 MIBC 被吞下后，它被设计为通过在腹部附近接近永久磁铁 (PM) 在胃内充气。但是，如果在 MIBC 仍在食道中时意外触发气球充气，则会损坏食道。因此，为了安全地为 MIBC 充气，我们的目标是跟踪 MIBC 沿食道的位置并确认 MIBC 通过。通常，基于磁传感器的跟踪系统往往体积庞大且成本高昂，因为它们涉及使用许多磁传感器进行计算密集型优化。为了解决这些问题，我们开发了一种算法，通过使用网格搜索结合动态限制搜索范围和搜索阈值调制来估计 MIBC 内 PM 的位置。我们的跟踪方法实现了 3.48 mm 的平均 1D 位置误差，与其他基于磁传感器的跟踪系统的平均误差高达 4 mm 相当，与我们的系统相比，这些跟踪系统需要更多传感器和计算能力。