sodium-pertechnetate-tc-99m and Osteosarcoma

Topics: Breast Neoplasms; Diphosphonates; Female; Humans; Middle Aged; Osteosarcoma; Radionuclide Imaging; Radiopharmaceuticals; Sodium Pertechnetate Tc 99m

A methotrexate-bisphosphonate conjugate containing a peptide bond has been found to possess over five times greater antineoplastic activity against osteosarcoma in experimental animal models compared with methotrexate alone.. The conjugate was labeled with 99mTc in the presence of stannous ions to determine biologic distribution, with special reference to osseous tissue. Biodistribution studies were carried out in mice after intravenous administration of the labeled conjugate. Radionuclide imaging of rabbits was also performed.. The labeled conjugate behaved like a bone-seeking agent.. The present study indicates that the concept of treating osteosarcoma or metastatic tumors of bone with this class of agents has a firm basis.

Topics: Animals; Antimetabolites, Antineoplastic; Bone and Bones; Bone Neoplasms; Diphosphonates; Male; Methotrexate; Mice; Osteosarcoma; Rabbits; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Tissue Distribution

The techniques of radioimmunoimaging and radioimmunotherapy suffer from prolonged high background radioactivity because intravenously injected antibodies remain in the circulation and in the organs far longer than necessary for effective binding to the target. To decrease background and increase radionuclide excretion without decreasing the dose of radioactivity delivered to the target tumor, we used radiolabeled biotinylated antibodies followed by a "chase" avidin injection.. A mouse monoclonal antibody, OST7 (IgG1), which reacts with human osteosarcoma, was biotinylated and labeled with 125I, 131I or 99mTc. Radiolabeled biotinylated OST7 (10 micrograms) was administered intravenously into nude mice bearing human osteosarcomas and 30 micrograms of avidin was injected intravenously 6 or 24 hr later.. Following avidin injection in mice pretreated with radiolabeled biotinylated antibodies, radioactivity was promptly cleared from the blood and deposited in the liver and spleen, after which radioiodine was rapidly detached from the antibody and excreted in the urine. The tumor-to-blood ratios at 6 and 24 hr after the injection of 125I-labeled biotinylated OST7 increased compared with the values before the avidin chase without any loss of tumor radioactivity. Furthermore, the tumor-to-background radioactivity ratio was improved and better images were obtained more rapidly after the injection of radiolabeled biotinylated antibodies than with conventional immunoscintigraphy.. This method may find application in clinical radioimmunoimaging, especially using short half-life radionuclides such as 99mTc and 123I.

Topics: Animals; Avidin; Bone Neoplasms; Female; Humans; Iodine Radioisotopes; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Osteosarcoma; Radioimmunodetection; Sodium Pertechnetate Tc 99m; Time Factors; Tissue Distribution

Primary extraosseous osteosarcoma of the thyroid gland is a rare tumor which is associated with a poor prognosis. In this report, we discuss such a tumor and its recurrence in a 78-yr-old female with multinodular goiter, focusing on the imaging evaluation of this unusual tumor.

Topics: Aged; Diphosphonates; Female; Humans; Neoplasm Recurrence, Local; Organotechnetium Compounds; Osteosarcoma; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Thyroid Neoplasms; Tomography, X-Ray Computed; Ultrasonography