**Table 1.**

*99mTC labelled radiotracers [20].*

### *Sentinel Lymph Node Biopsy for Early Oral Cavity Squamous Cell Carcinoma DOI: http://dx.doi.org/10.5772/intechopen.99410*

20 patients with floor of mouth OSCCs, where [99mTc]Tilmanocept may be of particular use, and a SLN was successfully identified in all cases without any false negatives [22]. A recent comparison study between [99mTc]Tilmanocept and [99mTc] Nanocolloid found that [99mTc]Tilmanocept had higher rates of clearance from the primary injection site but also had reduced accumulation within the SLN, with a similar SLN to injection site ratio of radioactivity between the two radiotracers [23].

#### **Figure 4.**

*Focused field of view with use of collimator. (This image is © 2021 Devicor Medical Products, Inc.; used with permission).*

This study demonstrated a high degree of agreement in the identification of SLNs between each radiotracer, however it is difficult to draw definitive conclusions with a small sample size, and further studies are required.

Specific surgical techniques can be employed to counteract the 'shine through' effect, including mobilisation of the fat pad between the submandibular gland and anterior belly of digastric to reflect the tissue, allowing for careful analysis with the handheld gamma probe while avoiding radiation from the primary tumour injection site [24]. A probe with an angled head (Neoprobe, Devicor Medical Products) with collimator attached is indispensable in such narrow spaces as in the neck to reliably locate the node. The collimator serves to decrease the field of view from 120 to 50 degrees while simultaneously increasing the spatial resolution of the probe (see **Figure 4**). Selective use of patent blue dye (Aspen Pharmacare) when the draining lymph nodes are in the submental and submandibular basins provides additional visual information to assist with identification of the SLN as demonstrated in **Figure 5**.
