Intraoperative hand-held imaging γ-camera for sentinel node detection in patients with breast cancer: feasibility evaluation and preliminary experience on 16 patients.

Purpose: This study aimed to assess the feasibility and potential usefulness of a new intraoperative portable high-resolution imaging γ-camera for the localization of sentinel lymph node in patients with breast cancer.
Methods: Sixteen T1 to T2 breast cancer female patients were evaluated (mean age, 62 years) with preoperative lymphoscintigraphy, acquired 30 minutes after intradermal injection of 60 to 70 MBq (1.6-1.9 mCi) of (99m)Tc-nanocolloids in saline volumes of 0.1 to 0.2 mL. Surgery took place the day after (18-20 hours after tracer injection). For intraoperative sentinel lymph node localization, a traditional γ-probe was used by the surgeon. Moreover, a portable imaging γ-camera was used by the nuclear physician who was present in the operating room.
Results: The portable imaging γ-camera showed very high spatial resolution (2.4 mm) in the 4.4 × 4.4 cm(2) FOV, with a good sensitivity of 180 cps/MBq at a Plexiglas depth of 1 cm. In 11 patients, lymphoscintigraphy, γ-probe, and imaging γ-camera depicted the same number of radioactive lymph nodes (17 nodes; 5 of which were metastatic and detected in 6 different patients). In 6 patients, the portable imaging γ-camera detected 1 node more than lymphoscintigraphy (in total, 5 nodes more), one of which was metastatic (the only one metastatic in that patient).
Conclusions: Our preliminary results showed that a portable high-resolution hand-held imaging γ-camera is a feasible, not time-consuming, noninvasive procedure in intraoperative sentinel node localization, offering extra confidence to the surgeon. In our hands, it was a very useful auxiliary imaging tool especially in the identification of nodes located deep in the axilla, which are difficult to detect at the preoperative lymphoscintigraphy. Additional multicenter studies involving a greater number of patients are necessary to confirm these promising data.