This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Imaging of Musculoskeletal Tumors, Subject name: Radiology
[{'content': 'Cold lesion on bone scan suggest: \nSelect and explain. \nA. Osteomyelitis, B. Lytic lesion, C. Osteoblastic Lesion, D. Sequestrum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: B. Osteoclastic activity:cold uptake Ref: Internet Source: Explanation: Interpretation of Bone scans Regional Hyperactivity may be due to: Normal bone growth and remodeling Increased Blood Flow (trauma, heterotopic ossification) Reactive osteoblastic activity (active infections, tumors) Reparative bone process (healing fractures, tumors, infections) Hyper-metabolic activity (metabolic disorders) They induce an increase in blood flow and osteoblastic activity.which enhance Ca / Phosphate local accretion into the hydroxyapatite matrix Cold Spots may be caused by: Malignant Tumors Lung (2-4%) Breast (5%) Renal (10%) Neuroblastomas (bone marrow mets) Thyroid (most cases) Multiple Myeloma (most cases) Bone Abscesses (they are surrounded by activity) Bone ischemia (AVN, sickle cell etc) Hemangiomas (normal or decreased activity)', 'role': 'assistant'}]