Isotope bone scan detects metabolic abnormalities in bone tissue by means of radionuclides, so it can show certain bone tissue lesions before abnormalities appear on X-ray and CT scans. It should be noted that bone scan is highly sensitive, with the disadvantage of low specificity, accurate localization of detected lesions, but difficult characterization, and some difficulty in differentiating tumorigenic from non-tumorigenic disease. However, bone scan can supplement other imaging examinations to clarify the clinical diagnosis. Warm tip: Bone tumors, arthritis, bone infarction, osteomyelitis, orthopedic surgery and fracture can appear as radioactive concentrations. Therefore, isotope bone scan is mainly used to screen for multiple bone lesions. It is only a screening and cannot be used as a qualitative diagnosis.