The most accurate diagnostic method for osteosarcoma is biopsy, where live tissue is extracted and sent for pathological examination. The positive rate of this method can reach over 90%. Besides biopsy, there are several other methods to examine such conditions. For example, X-rays can be taken to observe significant damage to the bone structure. Secondly, CT scans and MRI can be used to determine whether the bone tumor has infiltrated surrounding tissues. MRI can also detect if there are metastases to organs outside the lungs. The third method is radionuclide bone scanning, which primarily aims to check for distant metastases of osteosarcoma.