Scanning with L-(13 N) glutamate: Assessment of the response to chemotherapy of a patient with embryonal rhabdomyosarcoma

The use of (13) N-labeled L-glutamate as an imaging agent in a patient with embryonal rhabdomyosarcoma is described. Localization of (13)N in a large, poorly defined tumor of the left pectoral region was seen, and clinically occult right axilliary metastases were also detected. A marked reduction in uptake in these areas occurred after chemotherapy, paralleling the clinical disappearance of tumor. These changes were verified on gallium scan. (13)N-labeled glutamate may be useful as an imaging agent, especially in patients with soft-tissue sarcomas.