Magnetic marker clip (Magseed) localisation procedure

Why do I need this procedure?

• Before your surgery, the breast Surgeon needs a way to find the exact area in your breast that needs to be removed.
• A tiny marker called a magseed is placed in the breast to help guide the Surgeon during the operation.
• You may already have small marker clips in your breast from earlier biopsies.
• The magseed is different from theses because the Surgeon can find it in the operating theatre using a special scanner (probe).

What happens during this procedure?

• This procedure can be done up to four weeks before your surgery.

• If ultrasound is used:

  • You will lie on a bed while the Doctor looks at your breast with a scanner.
  • Your breast will be numbed with local anaesthetic so it should not hurt very much.
  • A needle holding the tiny magseed will be carefully placed into the area that needs treatment. The Doctor will use the ultrasound picture as a guide.
  • When the magseed is in the correct place, the needle will be removed, and the magseed will stay there.

• If X-rays are used:

  • Your breast will be placed in a mammogram machine.
  • Your breast will again be numbed with local anaesthetic.
  • The Doctor will use X-ray pictures to guide the needle with the magseed into the correct area.
  • A few pictures may be taken to make sure the magseed is in the best place.
  • Once it is in the correct position, the needle will be removed, and the magseed will stay there to mark the area for surgery.

What happens after the procedure?

• The staff will check that the area is not bleeding.
• A mammogram will then be taken to make sure the magseed is in the correct place for the Surgeons to find during the operation.
• A dressing will be placed over the area. It must stay on and be kept dry for 48 hours.

Are there any side effects?

• The most common side effect is a little discomfort when the local anaesthetic is injected into the breast.
• This usually only lasts for a few seconds.
• If X-rays are used, you may also feel some discomfort while your breast is positioned in the mammogram machine.

Preparation on the day

• Please do not wear deodorant.
• Please do not wear talcum powder.
• Please do not wear moisturiser.
• Please do not drive yourself to/from the appointment.

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

• You are taking any heart medication
• Anti-clotting tablets to thin your blood
• You have any drug allergies.

Contact our service

Tel: 020 7288 5888
Email: whh-tr.ImagingAppointments-WhittHealth@nhs.net
Opening hours: Monday to Friday 9am to 3pm