During a sentinel node biopsy, which agent is typically injected to trace lymph nodes?

• A. Radioactive dye
• B. Fluid is solution
• C. Surgical cement
• D. Non-steroidal anti-inflammatory drug

Answer: (A)

In a sentinel node biopsy, the typical agent injected to trace lymph nodes is a radioactive dye. This technique is employed to identify the first lymph node, known as the sentinel lymph node, that drains lymphatic fluid from a cancerous area.

The injection of radioactive dye allows for precise mapping of the lymphatic drainage pattern, which helps surgeons locate and remove the sentinel lymph node for examination. The radioactive properties of the dye enable imaging techniques, such as lymphoscintigraphy, to visualize the lymphatic system and identify the sentinel lymph node effectively.

This method is crucial in oncology for staging cancers and determining the presence of metastases, as it minimizes invasive procedures while still providing important diagnostic information. Other options presented, such as fluid solutions, surgical cement, or non-steroidal anti-inflammatory drugs, do not serve this specific purpose in sentinel node biopsies.