Breast cancer sentinel node scintigraphy: differences between imaging results 1 and 2 h after injection

Timing of image acquisition in breast cancer sentinel node scintigraphy remains a subject of debate. Therefore, the performance of our protocol in which images are acquired 1 and 2 h after injection was evaluated. The results of sentinel node scintigraphy 1 and 2 h after injection were compared with regard to the sentinel lymph nodes visualized.

We studied 132 patients who were consecutively referred for sentinel lymph node biopsy. 99mTc-albumine nanocolloid (120 MBq) was injected peritumourally into patients with palpable tumours and intratumourally into patients with nonpalpable tumours. All scintigraphic images taken for the sentinel node procedure were evaluated. The number of sentinel nodes per anatomic localization and the interpretability of the images were scored.

A total of 132 patients underwent sentinel node scintigraphy 1 h after injection. Of these, 117 patients also underwent sentinel node scintigraphy 2 h after injection. An axillary sentinel node was visualized in 79.5 and 95.7% of patients, respectively, 1 and 2 h after injection. In 20.5% of the patients the images acquired 1 h after injection did not show a sentinel node. Furthermore, in all procedures, the images 1 h after injection were of no added value to those acquired 2 h after injection.

Scintigraphic imaging 2 h after a single peritumoural or intratumoural administration of about 120 MBq 99mTc-albumine nanocolloid yields an axillary sentinel node in over 95% of cases. Imaging 1 h after injection is of no additional value and can be omitted.