CT scans are a type of more advanced imaging. It is a series of X-rays which are put together to provide imaging of tissues, organs, and skeletal structures. CT scan is sometimes used to assess the adjacent bone quality and look for flecks of calcium in the tumor to aid in diagnosis. It is also useful for detecting bony erosion from soft tissue masses. The information from a CT scan is often used to supplement that of an MRI. It can aid in diagnosis and help determine proximity to important structures. It is more useful than MRI in evaluating some types of bone tumors like osteoid osteoma. A CT scan of the chest is used to detect lung metastases from bone sarcomas. Soft tissue sarcomas can also spread to the liver so a CT scan of the chest, abdomen and pelvis may be performed. A CT scan is associated with radiation exposure since it involves X-rays.