Sentinel lymph node biopsy (SLNB) is crucial in the management of malignant melanoma treatment and is currently performed by pre-operatively inject a colloid nanomaterial labeled with Technetium (99mTc) as radioactive tracer. Intra-operatively, Patent Blue (PB) will be injected to improve the visualization of the lymphatic tract. However, current pre-operative SLN mapping technique, is associated with disadvantages as radiation exposure for both patients and health care personnel and logistic challenges, because of time constraints due to short half-live time of 99mTc.

Superparamagnetic iron oxide (SPIO) is novel, non-radioactive technique using a magnetic tracer (Magtrace® (Endomagnetics Ltd.)) and several studies showed that SPIO is non-inferior to dual tracing with 99mTc and PB in breast cancer patients. SPIO is expected to be non-inferior to dual tracing with 99mTc and PB in melanoma patients. However, further research is needed to demonstrate the use of SPIO in pre-operative Magnetic Resonance Imaging (MRI) scanning. Guidance on pre-operative MRI use is rather limited, though fundamental in the intended research process.

Hence, the aim of this subprotocol study, which includes healthy subjects, is to develop a pre-operative MRI protocol for melanoma patients. The acquired knowledge will be used to design a feasibility study, including a larger group of melanoma patients.

Inclusion Criteria:

• Healthy participants;
• Participants should be ≥18 years of age at the time of consent;
• Participants should be willing to provide informed consent.

Exclusion Criteria:

• Known intolerance/hypersensitivity to iron, dextran compounds or Magtrace® itself;
• Standard MRI exclusion criteria:
• Implantable (electrical) devices (e.g. pacemaker, cochlear implants, neurostimulator);
• Any other metal implants;
• Claustrophobia;
• MR-incompatible prosthetic heart valves;
• Tattoos inked with metallic dye.
• Participants who refuse to provide informed consent.