Breast Sentinel Lymph Node Injection

Why am I being referred for this injection?

A sentinel lymph node injection is given to patients who are undergoing breast surgery which includes a sentinel lymph node biopsy. The sentinel lymph node is the first lymph node on the lymphatic drainage system.  This injection helps the surgeon locate where your sentinel lymph node is, making the removal of it for biopsy a lot easier and more successful.

Is there anything I should tell the staff before the scan?

Yes. If you are pregnant or think you may be pregnant, please inform us. We also need to know if you are breastfeeding as you will need to stop breastfeeding for several hours following the scan.

Do I need to do anything to prepare for my injection?

No you will not have to do anything different to your normal routine before your injection. Eat and drink normally and take all your medication at your usual time.

What does your injection involve?

The member of staff doing your injection will need to get access to the breast that is going to be operated on. An injection containing a small amount of radioactivity will be injected under the skin on your breast using a very fine needle. The whole procedure will take up to 15 minutes though the injection itself takes just a few seconds.

Will my injection hurt? 

Some people feel a stinging sensation but this should not be too unpleasant as only a tiny volume of liquid is given.

Can l drive?

Yes, the injection will have no impact on your ability to drive.

What about work?

You may need to take an hour off on the day of your test. You will be able to return to work after the procedure.


You will be given a small amount of a radioactive substance for this procedure. The risks involved are minimal and a licensed doctor has judged that the benefits of doing the test outweigh the risks; if you wish to know more please see; if you still have questions regarding radiation risk please get in touch with us.

Alternative procedure

This is the best procedure to locate the sentinel lymph node, however a blue dye may also be given at the time of surgery to assist with finding the sentinel lymph node.

When do l get the results?

There are no results from the injection itself. The results of the biopsy will be given to you from your consultant but they will let you know how long this may take.

I still have more questions?

Don’t worry too much if you still have unanswered questions – a member of staff will go through the procedure with you when you arrive in the department and answer any questions you might have.

Contact number for advice

Medical Physics Department Tel: 0191 445 2710 Monday to Friday 8.30am to 4.30pm

Physicist/Head of Medical Physics Tel: 0191 445 2476 or 0191 445 5516 Monday to Friday 9am to 5pm