Advancing intraoperative magnetic tracing using 3D freehand magnetic particle imaging

Samaneh Azargoshasb, Lennert Molenaar, Giuseppe Rosiello, Tessa Buckle, Danny M. van Willigen, Melissa M. van de Loosdrecht, Mick M. Welling, Lejla Alic, Fijs W.B. van Leeuwen, Alexander Winter, Matthias N. van Oosterom*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

17 Citations (Scopus)
63 Downloads (Pure)


Purpose: Sentinel lymph node biopsy is a routine procedure for nodal staging in penile cancer. Most commonly, this procedure is guided by radioactive tracers, providing various forms of preoperative and intraoperative guidance. This is further extended with fluorescence imaging using hybrid radioactive–fluorescence tracers. Alternatively, a magnetic-based approach has become available using superparamagnetic iron-oxide nanoparticles (SPIONs). This study investigates a novel freehand magnetic particle imaging and navigation modality (fhMPI) for intraoperative localization, along with a hybrid approach, combining magnetic and fluorescence guidance. Materials and methods: The fhMPI set-up was built with a surgical navigation device, optical tracking system and magnetometer probe. A dedicated reconstruction software based on a look-up-table method was used to reconstruct a superficial 3D volume of the SPION distribution in tissue. For fluorescence guidance, indocyanine green (ICG) was added to the SPIONs. The fhMPI modality was characterized in phantoms, ex vivo human skin and in vivo porcine surgery. Results: Phantom and human skin explants illustrated that the current fhMPI modality had a sensitivity of 2.2 × 10–2 mg/mL SPIONs, a resolving power of at least 7 mm and a depth penetration up to 1.5 cm. Evaluation during porcine surgery showed that fhMPI allowed for an augmented reality image overlay of the tracer distribution in tissue, as well as 3D virtual navigation. Besides, using the hybrid approach, fluorescence imaging provided a visual confirmation of localized nodes. Conclusion: fhMPI is feasible in vivo, providing 3D imaging and navigation for magnetic nanoparticles in the operating room, expanding the guidance possibilities during magnetic sentinel lymph node procedures. Furthermore, the integration of ICG provides the ability to visually refine and confirm correct localization. Further clinical evaluation should verify these findings in human patients as well.

Original languageEnglish
Pages (from-to)211-218
Number of pages8
JournalInternational journal of computer assisted radiology and surgery
Issue number1
Early online date31 Jul 2021
Publication statusPublished - Jan 2022


  • Augmented reality
  • Fluorescence-guided surgery
  • Magnetic particle-guided surgery
  • Penile cancer
  • Surgical navigation


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