A 5D Magnetic Tracking System for Placement Verification of Umbilical Catheters and Endotracheal Tubes in Neonates

  • Liam Swanepoel

Student thesis: Doctoral Thesis


The use of subcutaneous medical devices has advanced the field of clinical medicine and surgery. However, localizing devices internally requires imaging techniques such as x-ray or ultrasound. A novel 5D magnetic tracking system for subcutaneous medical catheters is presented, providing the capability for precise device localization in an extremely compact and portable pocket-size format. It is entirely benign, avoids x-rays, and can be used to immediately confirm the proper instrument placement. The magnetic tracking system has been implemented on umbilical catheters and endotracheal tubes and is characterized by bench-test, cadaveric and in-vivo studies. The systems consist of a magnetic tip fixed to the distal end of the subcutaneous device, as well as a Magnetic Sensing Device that utilizes magnetic field sensors to localize the magnetic tip. Various Magnetic Sensing Devices have been developed, each with a specific use case in mind within the clinical environment. The magnetic tip is made from a soft, flexible, and lightweight magnetic composite material that is capable of sustaining a high magnetic remanence field whilst also being non-cytotoxic. The bench tests show high localization accuracy for a distance up to 4 cm. The accuracy is slightly reduced during cadaveric and in-vivo tests, due to external factors impacting the application, such as the dermal surface topography and the method of establishing the reference frame before radiographic imaging. A bias circuit has been developed and implemented to increase the operational depth of the magnetic tracking system and prevents sensor saturation at close distances. The magnetic tracking system has shown to be robust in performance and functionality in real-world clinical applications, and with its intuitive approach and portability, it has the potential to make real-time subcutaneous device tracking widely accessible.
Date of AwardNov 25 2022
Original languageEnglish (US)
Awarding Institution
  • Biological, Environmental Sciences and Engineering
SupervisorJurgen Kosel (Supervisor)

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