Locally increased uptake of fluorine-18-fluorodeoxyglucose after intracavitary administration of iodine-131-labeled antibody for primary brain tumors.
After the intracavitary administration of 131I-labeled monoclonal antibody for treatment of primary brain tumors after surgical resection, a persistent rim of 18F-fluorodeoxyglucose (FDG) accumulation surrounding the cavity can be observed on PET. This rim, although it accumulates more FDG than adjacent normal brain tissue, is not necessarily associated with tumor. In our study, we examine the characteristics of the rim that indicate persistent tumor and tumor progression.


METHODS
Sequential PET studies obtained after treatment in 10 patients were reviewed and the results correlated with dosimetry and post-treatment histologic diagnoses.


RESULTS
The rim of FDG accumulation was seen on the first post-treatment scan obtained 1-3 mo after therapy and persisted unchanged over the 2-26 mo follow-up period. Pathologically, the nonmalignant rim was associated with marked increase of macrophage infiltrates. Nodularity of the rim was associated with tumor.


CONCLUSIONS
Our study demonstrates that a rim of FDG accumulation is seen after intracavitary administration of 131I-labeled monoclonal antibody therapy independent of the presence of malignant disease. Malignant recurrence is suggested by the development of new nodularity in the rim of FDG accumulation.
Department of Nuclear Medicine, London Health Sciences Centre, England.
C J
CJ
Marriott
W
W
Thorstad
G
G
Akabani
M T
MT
Brown
R E
RE
McLendon
M W
MW
Hanson
R E
RE
Coleman
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D016499:Radioimmunotherapy; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D019063:Tenascin / Q000276:immunology; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019063:Tenascin; D019788:Fluorodeoxyglucose F18