X-rays are a form of ionizing radiation that can penetrate the body to form an image on film. Structures that are dense (such as bone) will appear white, air will be black, and other structures will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other diseases, especially when coupled with the use of barium and air contrast within the bowel.

This x-ray shows a malignant bone tumor (osteogenic sarcoma) of the knee. This type of tumor is usually seen in adolescents (around 15 years old). This tumor extends from the bone into the surrounding tissue.

This x-ray shows a malignant bone tumor (Ewing's sarcoma) of the upper arm bone (humerus). This type of tumor usually occurs during childhood and adolescence.

An abnormal growth of cells within the bone that may be benign or malignant (cancerous).