Quantitative scanning of osteogenic sarcoma with nitrogen-13-labeled L-glutamate.

N-13 L-glutamate was used to image an osteogenic sarcoma in a 9-year-old patient. Serial quantitative measurements of the amount of N-13 taken up by the primary tumor showed a decrease of 40% after 10 wk of chemotherapy. Blood-clearance data obtained from normal subjects indicate that more than 90% of the N-13 activity had left the blood before scanning of the tumor was begun. It appears that the N-13 label concentrated in the soft-tissue portion of this osteogenic sarcoma, whereas Tc-99m diphosphonate uptake was greatest in the regions where calcification was occurring.