Radioactive Seed Localizations (RSL)

Radioactive Seed Localization (RSL) is a procedure in which a tiny metal seed, about the size of a grain of rice, is placed into the breast or axilla to mark an area of abnormality.

The seed contains a small amount of radiation. Ultrasound and mammography imaging will be used to place the seed. During your surgery, your surgeon will use a radiation detection tool to locate the seed. The seed allows the surgeon to accurately locate the area of concern. The surgeon will then remove the seed and the abnormal tissue.

Referring a Patient for RSL

A Preoperative Breast Localization Booking form must be completed by a Mackenzie Health surgeon for patients to be referred for an RSL procedure at Mackenzie Health.

Please ensure the requisition form includes the referring surgeon’s information and signature, patient information and patient’s clinical history.

To obtain a copy of the Preoperative Breast Localization Booking form, visit the referral and consent forms page. Surgeon offices can fax a completed form to 905 883-2187.

How do I receive my appointment date and time?

Your surgeon's office will contact you with all appointments related to the RSL procedure. An automated call from the hospital will remind you of your RSL appointment 48 hours before the procedure.

How do I cancel or reschedule my RSL appointment?

If you need to cancel or reschedule your RSL appointment, please call your surgeon's office immediately.

Please do not come to the hospital for your RSL procedure if you plan to cancel or reschedule your surgery appointment.

How do I prepare for an RSL procedure?

You should not wear any powder or deodorant before the procedure. Your surgeon may have instructed you to stop taking certain medications, such as blood thinners. Let your surgeon’s office know if you are breastfeeding or if there is a chance you could be pregnant.

What do I do if I have an allergy to local anesthetics or latex?

If you have a known allergy to latex, please inform the diagnostic medical sonographer or mammography technologist who is performing your exam – non-latex material will be used during the exam.

If you have a known allergy to local anesthetic or any other medications used during the procedure, please inform the diagnostic medical sonographer or mammography technologist and the radiologist performing the procedure.

How long does an RSL procedure take?

An RSL procedure will take between one and two hours to complete.

What happens on the day of an RSL procedure?

The radioactive seed is inserted by a radiologist, either under ultrasound or mammography in the Medical Imaging department. The RSL is like the core biopsy procedure. You will visit the hospital as an outpatient a few days before your surgery to have the RSL procedure.

What happens after the RSL procedure?

You may bathe or shower on the same day, but do not get the bandages wet. These should be left on for 24 hours. You should avoid any strenuous activities and heavy lifting for two days, but you should be able to return to work and most activities the next day.

You may have some mild pain and bruising. If you notice any redness, swelling or drainage around the affected area, please call the Breast Health Clinic at 905-883-1212 ext. 3245 or your surgeon’s office.

We suggest you wear a comfortable supportive bra to lessen breast movement.

You will return to the hospital on the day of your surgery and check in again at Patient Registration. The surgeon will remove the seed and the abnormal tissue.

Who do I contact if I have any concerns after the RSL procedure?

If you have any concerns about your breast after the RSL procedure, please contact the Breast Health Clinic at 905-883-1212 ext. 3245 or your surgeon. If your surgeon’s office is unavailable, please visit the Mackenzie Health Emergency Department.

If there is any event that would keep you from having the radioactive seed removed on the scheduled surgery date, please call your surgeon’s office.

If you are unable to call, please have someone else call for you.

If your appointment is at Mackenzie Richmond Hill Hospital:

  • You may park in one of the visitors parking lots (North or South) and make your way to the C-Wing or D-Wing entrance.
  • Please allow yourself extra time during peak hours, as finding parking can take longer than expected. If possible, consider taking public transit, or getting dropped off by a family member or friend.

If your appointment is at Cortellucci Vaughan Hospital:

  • You may park in the visitor parking lots at the west of the building. 
  • Access to the hospital is through the Main Entrance at the south side of the building (6:30 a.m. – 10 p.m.) or through the west of the hospital (24/7 access). Drop-off  and pick-up is available at both entrances.

View more information on parking services.

Once inside the hospital, please check in at Patient Registration using our self-serve kiosks. 

Mackenzie Richmond Hill Hospital

10 Trench St.
Richmond Hill, ON L4C 4Z3
Local to Richmond Hill: 905-883-1212
Local to Vaughan: 905-417-2000
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Cortellucci Vaughan Hospital

3200 Major Mackenzie Dr W
Vaughan ON L6A 4Z3
Local from Vaughan: 905-417-2000
Local from Richmond Hill: 905-883-1212
View the map for this location