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Magtrace® insertion

Patient information factsheet

What is Magtrace®?

  • Magtrace® is a medical dye (called a ‘tracer’) used in breast cancer surgery to help Surgeons find sentinel lymph nodes.
  • Sentinel lymph nodes are the first lymph nodes where breast cancer may spread. They are usually in the underarm.
  • Magtrace® contains tiny iron oxide particles mixed in a liquid.
  • It is not radioactive.

Why is Magtrace® used?

  • Magtrace® helps the Surgeons:
    • Find sentinel lymph nodes accurately.
    • Check whether breast cancer has spread to nearby lymph nodes.
    • Avoid removing more lymph nodes than necessary.
    • Can reduce side effects such as arm swelling (lymphoedema).

How does Magtrace® work?

  1. Magtrace® is injected directly into the breast tissue.
  2. The iron particles travel through the lymphatic system.
  3. Sentinel lymph nodes absorb the particles.
  4. During surgery, the Surgeon uses a special magnetic probe to detect the nodes containing Magtrace®.

When is Magtrace® given?

  • It can be given just before surgery or up to 30 days before.
  • A Surgeon or Breast Nurse Specialist can give the injection in a breast clinic.
  • Or a Consultant Radiologist or Advanced Practitioner can give it in the imaging department.

Are there any side effects?

  • Very serious side effects, like anaphylaxis (a severe allergic reaction), are extremely rare.
  • Common side effects include:
    • Temporary skin staining (brown/grey colour) at the injection site – this usually fades over time but can last for several months in some people.
    • Mild pain or swelling.

Is Magtrace® safe?

  • Yes, Magtrace® is not radioactive and involves no exposure to ionising radiation.
  • It is broken down naturally by the body over time.
  • It has been approved for clinical use in the NHS and is widely used in breast surgery.

Can Magtrace® affect scans?

  • Magtrace® can change how a breast MRI scan looks for a while after it is used.
  • This is because Magtrace® contains tiny iron particles. MRI scans use strong magnets, so those particles can affect the image.
  • Always tell medical staff if you have had Magtrace® before you have an MRI scan.

Advantages of Magtrace®

  • No radiation is used
  • Can be given at different times before surgery
  • Helps Doctors find the first lymph nodes accurately
  • May mean fewer lymph nodes need to be removed.

Preparation on the Day

  • Do not put on deodorant, powder or creams on your breasts or underarm area within two hours of your procedure, as these products can affect your results.

  • Please do not drive yourself to/from the appointment. Arrange for a friend/family member to bring/collect you (you can then both use public transport if they do not have a private vehicle). Otherwise, please take a taxi.

  • Please ring the Imaging Department on 020 7288 5888 (Monday to Friday 9am to 3pm) and ask to speak to the Breast Imaging Team before your appointment if:

    • you are taking any heart medication
    • or anti-clotting tablets to thin your blood
    • or if you have any drug allergies.

Contact our service

Tel.: 020 7288 5888, Monday to Friday 9am to 3pm.

Email: whh-tr.ImagingAppointments-WhittHealth@nhs.net

Published:
08 Jun 2026
Review:
08 Jun 2028
Reference:
ACW/Imag/MagtrIns/01