Usefulness of a solid-state gamma camera for sentinel node identification in patients with breast cancer

A solid-state gamma camera was recently developed. This tool may enable intra-operative imaging of sentinel nodes in breast cancer. The aim of the present study was to evaluate the usefulness of a solid-state gamma camera for the pre- and intra-operative identification of sentinel nodes in patients with breast cancer.

Breast cancer patients with clinically negative nodes underwent sentinel node biopsy using dye and radioisotopes. Lymphoscintigraphy using both the conventional Anger camera and the solid-state gamma camera was performed the day before surgery. Sentinel nodes were intra-operatively identified using the gamma probe and imaged with a solid-state gamma camera, and then excised. When several sentinel nodes were present, these steps were repeated.

Twenty-nine patients (30 basins) were enrolled in the study. The mean patient age was 54 years and the mean tumor size was 16 mm. A total of 41 sentinel nodes were identified using the Anger camera or the solid-state gamma camera pre-operatively. Thirty-eight sentinel nodes (92.7%) were identified using both the Anger camera and the solid-state gamma camera, 1 sentinel node (2.4%) was identified using the Anger camera alone, and 2 sentinel nodes (4.9%) were identified using the solid-state gamma camera alone. A total of 63 sentinel nodes were identified using the gamma probe or the solid-state gamma camera intra-operatively, and were excised. Fifty-seven sentinel nodes (90.5%) were identified using both the gamma probe and the solid-state gamma camera, 3 sentinel nodes (4.8%) were identified using the gamma probe alone, and 3 sentinel nodes (4.8%) were identified using the solid-state gamma camera alone.

The solid-state gamma camera is useful for pre- and intra-operative identification of sentinel nodes in breast cancer. The significance of the solid-state gamma camera could be that it compensates for the gamma probe when the gamma probe cannot identify some sentinel nodes because of the shine through effect, and avoids leaving the residual sentinel nodes behind the axilla intra-operatively.