Objective To explore the diagnostic efficiency of ⁹⁹Tc^m-Rituximab SPECT/CT for sentinel lymph node (SLN) in breast cancer.

Methods Clinical data of 22 female patients with breast cancer confirmed by histopathological examination in Hainan Cancer Hospital from July 2019 to July 2020 were retrospectively analyzed. The patients aged between 37 and 73 years (the median age was 50.5 years). They underwent ⁹⁹Tc^m-Rituximab SPECT/CT imaging before surgery. The images were analyzed, and the number of SLN was counted. Operation was performed 1–2 h after the imaging, and a portable γ detector was used to detect SLN during the operation. The diagnostic efficacy of ⁹⁹Tc^m-Rituximab was evaluated using the number of SLN detected during the operation as the "gold standard".

Results A total of 67 SLNs were detected by SPECT/CT imaging, most of which were 1–3 (68%, 15/22). A total of 81 SLNs were detected by γ detectors during the operation, and the majority of them were 2–4 (73%, 16/22). The sensitivity of ⁹⁹Tc^m-Rituximab imaging was 100% (22/22) when taking patients as unit, and the total coincidence rate was 100% (22/22). The sensitivity was 83% (67/81), the positive predictive value was 100% (67/67), and the total coincidence rate was 83% (67/81) when taking lymph node as unit.

Conclusion ⁹⁹Tc^m-Rituximab SPECT/CT has high sensitivity and coincidence rate in the diagnosis of SLNs in breast cancer, and it has good clinical application.