Magseed® marker

Frequently asked questions

What is a “Magseed®”?

The Magseed® marker is a tiny metal seed designed to mark cancers. It’s made out of surgical grade stainless steel and is located using its magnetic trace.

What is Magseed® marker localisation?

‘Magseed® localisation’ is the technique developed to allow radiologists and surgeons to mark and remove small and early stage breast cancers with incredible precision.

How long does a Magseed-guided breast lumpectomy operation take?

The removal of the Magseed® marker can take as little as five minutes but the overall duration of your surgery will depend on the additional procedure you may be having.

How much do Magseed® markers cost?

This differs from country to country. There are many assessments of seed localisation that have shown significant cost savings for the hospital. Follow this link to get in touch with your nearest sales distribution partner directly.

How big is a Magseed® marker?

The Magseed® marker is approximately 5mm x 1mm (a fraction smaller, in fact). We typically say that’s smaller than the size of a grain of rice, but if you think there’s a better comparison, please let us know. Anyway, just know that it’s the smallest available.

How does a Magseed® marker work?

The Magseed® marker is detected using our Sentimag® probe. When the marker is placed in the breast or marked lesion, it is totally inert. It is only when the probe is passed near the seed that it becomes detectable.

Learn more about how the Sentimag® probe works here.

How long does a Magseed® marker stay active?

Although the Magseed® marker is inert when not in use, it will always be detectable no matter how far ahead of surgery it is placed. Effectively, it has the same signal from day one to day 1,000.

Take a look at the indications for use page to see the approved length of implantation time the Magseed® marker has in your territory.

How does a Magseed® marker differ from a guide-wire?

In lots of ways! Too many to list in a short FAQ in fact. To begin to explain the differences, it features as part of our ‘Why Magseed‘ page.

How does a Magseed® marker differ from a radioseed?

In some ways they’re quite similar; small, accurate and convenient, but there are a number of crucial differences, namely that the Magseed® marker is non-radioactive, and therefore does not decay like a radioseed does.

How is the Magseed® marker placed in the breast?

The Magseed® marker has an ‘end-deploy’ system, this simply means that where you place the tip of the needle is where the seed will be placed. That makes it very easy to accurately deploy the seed. Ideally, the Magseed® marker should be placed in the centre of the lesion.

It can be placed in the breast using Ultrasound, Stereotactic, Tomographic or Mammographic image guidance, depending on preference or tumour type.

Introducer needles are currently available in 7cm and 12cm versions.

Can patients with Nickel allergies have a Magseed® marker?

The Magseed® marker is not officially indicated for use in Nickel allergic patients. However, compared to a stainless-steel guide wire, a Magseed® marker offers significantly less exposure to Nickel.

Normal Surgical grade stainless steel contains around 10-15% Nickel. The surgical grade stainless steel used for the Magseed® marker contains less than 0.23% Ni content.

Can a Magseed® marker migrate?

The likelihood of a Magseed® marker migrating is extremely low due to its small size. It’s twisted structure helps to promote tissue in-growth which anchors it firmly into the tissue to reduce migration.

See our ‘Magseed clinical data‘ page to see studies where it has demonstrated to have a similar migration rate as a radioseed, which is <1%. This has been proven in published studies involving thousands of patients.

What about MRI?

A Magseed® marker cannot currently be placed under MRI guidance because the deployment needle is made of stainless steel. However, it is okay for a patient with a Magseed® marker implanted to have an MRI (1.5T & 3.0T) without causing any heating or movement of the seed.

Just like any clip, it will cause some level of void artefact but will vary depending on the sequence you use. We have commonly seen a 2-4cm artefact. However, as this is a lesion localization device and not a biopsy site marker, it’s quite rare that a patient would need an MRI whilst the Magseed marker is in place.

How can I evaluate or get Magseed?

Type your details on this form and someone will be in touch soon to arrange an evaluation.

Where can I ask further questions?

If you’ve not found the answer you are looking for, please get in touch with our team.


*Data on file at Endomag. †Clinical references available on our Clinical data page.

Indications may vary in different countries; please either visit our Indications page, consult the appropriate IFU or your local distributor for more information.