5. Scintigraphy

For the determination of the sentinel lymph node, we used the Tc-nanocolloid. We used Nanocoll, produced by Amersham Health (Italy). Nanocoll is a set for the preparation of 99 m Tc-albumin nanocolloid. At least 95% of the parts of this colloid are equal or smaller than 80 nm.

We used 2–4 mCi, which correlates to 7,4–14,8 mBq. The amount of the radiocolloid used depended on the size of the tumor. Radiocolloid was injected at four different areas in close proximity to the tumor (above, below, left, and right; or clockwise—12, 3, 6, and 9 o'clock). By changing the needle positioning, we are able to infiltrate by colloid the entire tumor region. After the injection of the radiocolloid, the patient rinsed their mouth with water to remove any possible radiocolloid residues which might have influenced the investigation. 10 minutes after the application of the radiocolloid, we started to follow its movement along the lymphatics into the closest lymph nodes. For the detection of the radiocolloid, we used a gamma-ray camera Picker SX 300. Dynamic scintigraphy lasted between 45 and 60 min.

After an hour, we also made static recordings in the anteroposterior and lateral projections. Static scintigraphy allowed for the marking of the sentinel lymph node location on the overlying skin of the neck. If we were unable to identify the sentinel lymph node after an hour, we repeated the static recordings again in 30 min.

In this way, with the use of static and dynamic scintigraphy, we were able to identify the correct sentinel lymph nodes and limit any possible "skip" metastases [23].
