Abstract: When it comes to ⁹⁹Tc^m-MDP bone scintigraphy, normal and abnormal bone tissue can uptake skeletal imaging agent, so does the extraosseous tissue, especially the thorax soft tissue. The understanding of the possible explanations for the abnormal ⁹⁹Tc^m-MDP uptake in the thoracic tissue on bone scintigraphy is of great importance to clinical diagnosis. The relevant reports about this field in recent years are reviewed.