**7. Lymphoscintigraphy and sentinel lymph node in oral and maxillofacial surgery**

Sentinel lymph node was first described in 1980s when Donald L. Morton, a surgeon at the John Wayne Cancer Center in Santa Monika, and his pathologist Alistair J. Cochran suggested the idea of lymph node mapping with biopsy of the sentinel lymph node in melanoma. They described the sentinel lymph node as the first node, which is the first portal in the diseased cell migration from the lesion. They proposed the importance of the first node on the localization of the lesion. In their paper they emphasized that a "sentinel node" is the initial lymph node upon which the primary tumor drains. Today we know that the sentinel lymph node is the first node on the lymphatic pathway that drains directly from the tumor [41].

SLNB was initially used in melanoma and breast cancer. The indications are melanoma with Breslow thickness up to 1mm, high-risk squamous cell carcinoma, and Merkel carcinoma. Due to the anatomical complexity of the lymphatic pathways in the head and neck region, its importance has been recently appreciated in oncology. To avoid unnecessary neck dissection to decrease the morbidity and improve the patient's quality of life, it is suggested to perform SLNB also in head and neck cancer patients.

Cervical lymph node involvement status is the crucial deciding element in staging, management and predicting prognosis in patients with head and neck SCC.

Recent studies have shown the potential of SLNB as a minimally invasive procedure for assessing occult metastasis and thus reducing morbidity in patients undergoing elective neck dissection (END). Its reliability in T1-T2N0 in the oral cavity and oropharyngeal cancers has been validated for more than a decade, yet till today there is no consensus reached as to when and on whom to perform.

In the field of nuclear medicine, the sentinel lymph node is the first node that is visible after the administration of the tracer. Flow imaging or "dynamic phase" is the first phase, immediately after injection, which shows the lymphatic pathway and clearance. In the late stage also known as the "static phase", can the very first node or sometimes more than one node be visualized and anatomically pinpointed.

Lymphatic mapping is performed with either radiolabeled tracers or vital blue dye (VBD). In conventional lymphoscintigraphy, the main tracer is technetium 99m-labeled radio colloids. The most widely used radiotracer in the United States is technetium 99m-sulfur colloid, and in Europe technetium 99m-albumin-basednano colloid is used. They both, however, lack optimal rapid clearance of the injection site, high accumulation within the first node, and minimal tracer uptake in the distant nodes [42].

Recently, to overcome the limitations of the conventional colloid tracers, a new tracer has been developed to fulfill the aforementioned shortcomings. Technetium 99m-diethylenetriaminepentaacetic acid (DTPA)-mannosyl-dextran (also known as 99mTc-tilmanocept) is a novel radiopharmaceutical agent that selectively binds to CD206 receptors, which presents in high concentration in lymph nodes on the membrane of macrophages and dendritic cells. Tilmanocept structure consists of a dextran main domain and the DTPA as well as mannose units which are attached to the central part. The average diameter of this macromolecule is 7nm. The mannose binds to the CD206 receptor, whereas the DTPA serves as the binding part for

#### **Figure 7.**

*Sentinel node scintigraphy in a patient with SCC of the soft tissue between the body of mandible and the hyoid bone (orange arrow) and negative clinical examination as well as normal lymph node status in MRI. To avoid radical neck dissection sentinel node scintigraphy has been performed to detect the nodes with direct drainage from the lesion. After 60 min, two cervical lymph nodes were visualized (white and yellow arrows). (A) Axial view, (B) sagittal view, and (C) planar image.*

technetium 99m. Due to its small size, it has a rapid uptake in lymph nodes, and its targeted binding prevents its migration to distal nodes [43, 44].

Recent studies have shown the high sensitivity and specificity of up to 94% of tilmanocept in patients with head and neck squamous cell carcinoma [45, 46]. Assessment of single-photon emission computed tomography with computed tomography (SPECT/CT) in addition to planar lymph scintigraphy provides precise anatomical localization in clinically negative nodal status and early stages of the head and neck cancers [24] (**Figure 7**).

#### **8. Conclusion**

Diagnosis of cancer and inflammatory diseases and the differentiation between the two are of utmost importance. Nuclear medicine by using radionuclide substances can detect the dynamic aspect of a disease process, and when this dynamic study is mingled by a morphological study, CT or MRI, the management team can see a clearer picture of the disease process and plan treatment protocols accordingly. Sentinel lymph node biopsy is gaining momentum in cancer treatment protocols as a MUST-DO procedure before the definitive treatment plan is implemented.

**93**

**Author details**

Graz, Graz, Austria

Tina Nazerani\*, Peter Kalmar and Reingard M. Aigner

provided the original work is properly cited.

Division of Nuclear Medicine, Department of Radiology, Medical University of

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: tina.nazerani-hooshmand@medunigraz.at

*Emerging Role of Nuclear Medicine in Oral and Maxillofacial Surgery*

*DOI: http://dx.doi.org/10.5772/intechopen.92278*

#### **Conflict of interest**

The authors declare no conflict of interest.

*Emerging Role of Nuclear Medicine in Oral and Maxillofacial Surgery DOI: http://dx.doi.org/10.5772/intechopen.92278*

*Oral and Maxillofacial Surgery*

*view, (B) sagittal view, and (C) planar image.*

head and neck cancers [24] (**Figure 7**).

The authors declare no conflict of interest.

*Sentinel node scintigraphy in a patient with SCC of the soft tissue between the body of mandible and the hyoid bone (orange arrow) and negative clinical examination as well as normal lymph node status in MRI. To avoid radical neck dissection sentinel node scintigraphy has been performed to detect the nodes with direct drainage from the lesion. After 60 min, two cervical lymph nodes were visualized (white and yellow arrows). (A) Axial* 

technetium 99m. Due to its small size, it has a rapid uptake in lymph nodes, and its

Recent studies have shown the high sensitivity and specificity of up to 94% of tilmanocept in patients with head and neck squamous cell carcinoma [45, 46]. Assessment of single-photon emission computed tomography with computed tomography (SPECT/CT) in addition to planar lymph scintigraphy provides precise anatomical localization in clinically negative nodal status and early stages of the

Diagnosis of cancer and inflammatory diseases and the differentiation between the two are of utmost importance. Nuclear medicine by using radionuclide substances can detect the dynamic aspect of a disease process, and when this dynamic study is mingled by a morphological study, CT or MRI, the management team can see a clearer picture of the disease process and plan treatment protocols accordingly. Sentinel lymph node biopsy is gaining momentum in cancer treatment protocols as

a MUST-DO procedure before the definitive treatment plan is implemented.

targeted binding prevents its migration to distal nodes [43, 44].

**Figure 7.**

**8. Conclusion**

**Conflict of interest**

**92**
