# Tracking the Traveled Distance of Capsule Endoscopes along a Gastrointestinal-Tract Model Using Differential Static Magnetic Localization

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## Abstract

**:**

## 1. Introduction

## 2. Methods

#### 2.1. Differential Static Magnetic Tracking

#### 2.2. Experimental Setup

#### 2.3. Evaluation Procedure

## 3. Results

## 4. Discussion

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 1.**Schematic of the system design using the differential method to track the traveled distance of a capsule endoscope within the gastrointestinal tract.

**Figure 2.**Localisation setup with the 12 sensors centered within the sensor mounts. The coordinate system of the setup is in its centre. The printed trajectory with the 10 × 10 mm magnet was exemplarily placed at the $z=0$ mm plane.

**Figure 3.**Schematic of the evaluation procedure for calculating the mean and standard deviation (STD) of the relative distance error and orientation error for each magnet, and its corresponding orientation.

**Figure 4.**Mean and standard deviation values for relative traveled distance errors for different magnets and orientations. For the 5 and 3 mm long magnets, cases where the magnetisation was in parallel with the moving direction were not conducted.

**Figure 5.**Representative measured trajectories using the 10 × 10 mm magnet while its magnetisation was perpendicular to the movement direction.

**Figure 6.**Mean and standard deviation values of orientation errors for magnets along the trajectory in perpendicular orientation to the moving direction.

**Table 1.**Comparison with state-of-the-art capsule endoscopy tracking methods. The occupied space is specified with respect to the assumed typical size of commercial capsules of 33 × 12 mm (length × diameter).

Method | Trajectory | Occ. Space (%) | Rel. Error (%) | Or. Error (${}^{\circ}$) | |
---|---|---|---|---|---|

This work: | |||||

10 mm magnet | Diff. static magnetic | Curved 3D (487.5 mm) | 21.0 | 2.7 | 1.7 |

5 mm magnet | Diff. static magnetic | Curved 3D (487.5 mm) | 10.5 | 4.3 | 2.0 |

3 mm magnet | Diff. static magnetic | Curved 3D (487.5 mm) | 6.3 | 11.9 | 3.6 |

State of the art: | |||||

[19] (2019) | Static magnetic | Curved 3D (840 mm) | not stated | 5.7 | - |

[18] (2021) | Diff. static magnetic | Linear (109 mm) | 21.0 | 3.1 | 2.7 |

[9] (2019) | Video | Linear (200 mm) | 0 | 6.0 | - |

[10] (2021) | Video/Inertial unit | Linear (600 mm) | >100 | 3.7 | - |

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**MDPI and ACS Style**

Zeising, S.; Chen, L.; Thalmayer, A.; Lübke, M.; Fischer, G.; Kirchner, J.
Tracking the Traveled Distance of Capsule Endoscopes along a Gastrointestinal-Tract Model Using Differential Static Magnetic Localization. *Diagnostics* **2022**, *12*, 1333.
https://doi.org/10.3390/diagnostics12061333

**AMA Style**

Zeising S, Chen L, Thalmayer A, Lübke M, Fischer G, Kirchner J.
Tracking the Traveled Distance of Capsule Endoscopes along a Gastrointestinal-Tract Model Using Differential Static Magnetic Localization. *Diagnostics*. 2022; 12(6):1333.
https://doi.org/10.3390/diagnostics12061333

**Chicago/Turabian Style**

Zeising, Samuel, Lu Chen, Angelika Thalmayer, Maximilian Lübke, Georg Fischer, and Jens Kirchner.
2022. "Tracking the Traveled Distance of Capsule Endoscopes along a Gastrointestinal-Tract Model Using Differential Static Magnetic Localization" *Diagnostics* 12, no. 6: 1333.
https://doi.org/10.3390/diagnostics12061333