Introduction: In Brazil, breast cancer is the most important cancer among women, both by his mortality, as evidenced by its frequency. Due to the growing trend of conservative treatment of breast cancer largely attributed to early detection of disease, biopsy of the sentinel lymph node (SLN) has become the standard technique for axillary staging in various institutes, with great results of sensitivity, allowing the reduction of unnecessary axillary dissection, with low rates of axillary recurrence, less postoperative complications, and significant improvement in quality of life of patients (MILTENBURG et al., 1999). SLN is based on the existence of an order of lymphatic progression in the solid tumors, where the first lymph nodes (sentinels) receiving the lymph from the tumor would present the power of predicting the status remaining lymphatic chain. Lymphoscintigraphy represents a valuable technique for identifying lymphatic pathways and SLN, and it is an examination of Nuclear Medicine which allows the study of functionally active lymph nodes, safely and less invasive as compared to lymphangiography (FOGELMAN, 1994).

Objectives: Understanding lymphoscintigraphy for search of sentinel lymph node in breast cancer and point out the advantages of this technique along with radioguided surgery.

Material and Methods: An analysis was held from the lymphoscintigraphy technique, used in a reference institute of Nuclear Medicine for search of sentinel lymph node. The search of SLN consists of two stages: lymphoscintigraphy and radioguided intraoperative localization with aid of the gamma-probe (FLEURY, 2012).

Results: In breast cancer, the location of the SLN determines the axillary status, because if lymph node is negative, this will avoid the axillary dissection; since the lymphedema of upper limb is a frequent consequence of the breast surgeries plus axillary dissection, a swollen arm causes patient´s embarrassment in their daily activities, it reduces self-esteem by the distortion of body image, inferring in the personal relationship, and leads to a discomfort in social interaction.

Conclusion: Lymphoscintigraphy is currently advocated as the main diagnostic test for peripheral lymphatic system, allowing the visualization of lymphatic vessels and lymph nodes. SLN, for being the first lymph node to receive lymphatic drainage from a tumor (FONSECA, 2002), is also what enables the surgeon remove it safely and in a less invasive, allowing the pathologist to check whether or not metastatic commitment, indicating or not the axillary dissection in a patient who was affected with breast cancer. The axillary lymph node staging, besides being an important prognostic predictor in this initial cancer, contributes to the decision of adjuvant therapy.