Osteosarcoma can be detected through characteristic changes in X-ray imaging, such as the Codman's triangle, which usually occurs around the joints at the metaphyseal ends of the long tubular bones in the limbs. This leads to the destruction of the trabeculae and increased density of the tumor tissue, which can break through the cortical bone. The tumor can lift the periosteum to form the characteristic Codman's triangle. Therefore, orthopedic doctors can preliminarily diagnose it as a bone tumor or osteosarcoma based on the appearance in this X-ray. Additionally, diagnosis should be correlated with clinical symptoms such as the presence of a noticeable mass, pain, tenderness in the localized area, and general symptoms of cachexia, such as weight loss, anemia, fever, and malaise.