An Ultralow-Dose 1-Day Protocol With Activities Lower Than 20 MBq for the Detection of Sentinel Lymph Nodes in Breast Cancer—Experiences After 150 Cases

INTRODUCTION: Common protocols for the detection of sentinel lymph nodes in early breast cancer often include the injection of the tracer 1 day before surgery. In order to detect enough activity on the day of surgery, the applied activity in many protocols is as high as several hundred MBq. So far, very few protocols with an activity below 20 MBq have been reported. We developed an ultralow-dose 1-day protocol with a mean activity lower than 20 MBq in order to reduce radiation exposure for patients and staff. Here, we are presenting our experiences in 150 consecutive cases. MATERIALS AND METHODS: A total of 150 patients with clinically and sonographically negative axilla and no multicentricity underwent a sentinel lymph node biopsy using an ultralow-dose protocol performed on the day of surgery. No patient received systemic therapy prior to sentinel node biopsy. After peritumoral injection of the tracer Technetium-99m, a lymphoscintigraphy was performed in all cases. Seven minutes before the first cut, we injected 5 mL of blue dye in the region of the areola. RESULTS: In 148 (98.7%) of 150 patients, at least 1 sentinel lymph node could be identified by lymphoscintigraphy; the detection rate during surgery with combined tracers Technetium-99m and blue dye was 100%. The mean applied activity was 17.8 MBq (9-20). A mean number of 1.3 (0-5) sentinel lymph nodes were identified by lymphoscintigraphy and a mean number of 1.8 (1-5) sentinel lymph nodes were removed during sentinel lymph node biopsy. CONCLUSION: Ultralow-dose 1-day protocols with an activity lower than 20 MBq are a safe alternative to 1-day or 2-day protocols with significantly higher radiation doses in primary surgery for early breast cancer. Using Technetium-99m and blue dye in a dual tracer approach, detection rates of 100% are possible in clinical routine in order to reduce radiation exposure for patients and staff.