title: Imaging of primary Ewing sarcoma with 13N-L-glutamate.
abstract: Eleven patients with untreated primary Ewing sarcoma were studied with intravenously administered 13N-labeled L-glutamate. Seven were repeatedly scanned during chemotherapy using this agent and 99mTc-methylene diphosphonate (99mTc-MDP). The untreated primary tumor was distinctly visualized with 13N-L-glutamate in all cases; the distribution of 13N label in the tumor sometimes differed from that of 99mTc. A kinetic study showed rapid uptake of 13N by tumor tissue. Repeat scans following therapy indicated that 13N-L-glutamate and 99mTc-MDP uptake showed changes consistent with histological findings following subsequent surgery. 13N uptake often decreased more markedly than 99mTc uptake during chemotherapy, but metastatic lesions were not visualized with 13N-L-glutamate. Tumor imaging with this labeled amino acid may be of value in assessing the response of primary Ewing sarcoma to chemotherapy.
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D002648:Child; D004164:Diphosphonates; D005260:Female; D005971:Glutamates; D018698:Glutamic Acid; D006801:Humans; D008297:Male; D008875:Middle Aged; D009590:Nitrogen Radioisotopes; D011877:Radionuclide Imaging; D012512:Sarcoma, Ewing / Q000000981:diagnostic imaging* / Q000556:secondary / Q000628:therapy; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy; D013667:Technetium; D013669:Technetium Tc 99m Medronate
chemical_list: D004164:Diphosphonates; D005971:Glutamates; D009590:Nitrogen Radioisotopes; D018698:Glutamic Acid; D013667:Technetium; D013669:Technetium Tc 99m Medronate