Role of Tc-99m MIBI and Tc-99m DMSA-V in Evaluation of Bone Tumors

Background: Bone sarcomas are usually aggressive tumors treated by multimodality approaches. Early detection of residual or recurrent tumor tissue after treatment is important in the management of these patients. This is currently achieved by clinical examination, diagnostic radiological procedures, radionuclide imaging techniques and detailed histological examination. Tumor response to preoperative chemotherapy in osteosarcoma as defined by the degree of tumor necrosis, has been found to be one of the best prognostic indicators of disease control. However, this information can be only obtained by detailed histologic examination after tumor resection. Recently, there have been attempts to predict the tumor response to chemotherapy before surgical excision by radionuclide imaging techniques. This enables the clinician to consider alternative chemotherapeutic regimens or surgery at an earlier stage. Purpose: Evaluate and compare Tc-99m pentavalent DMSA to Tc-99m sesta MIBI and Tc-99m MDP blood pool image in patients with malignant bone tumors for the purpose of: 1- Detection of the primary lesion. 2- Evaluating treatment response of osteosarcoma after 4 cycles of preoperative chemotherapy. 3- Prediction of response of osteosarcoma after the first cycle only of preoperative chemotherapy.