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.