What causes false-positive and false-negative results on breast cancer lymphoscintigraphy (sentinel lymph node mapping)?

Updated: Dec 13, 2018
  • Author: Durre Sabih, MBBS, MSc, FRCP(Edin); Chief Editor: Mahan Mathur, MD  more...
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Answer

Answer

A false-positive result may be caused by contamination of the skin or residual activity from another nuclear medicine procedure done recently.

A false-negative result (absent or faint lymph node uptake) may be caused by a low radiopharmaceutical dose, poor radiopharmaceutical quality, insufficient radiocolloid particles, imaging time that is too early or too late, advanced patient age, or tumor replacement of nodes.

One way of reducing false-positive and false-negative results is to combine the visual assessment of nodes with intraoperative gamma counting and digital palpation through the surgical incision. [15]


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