Assessment of progression and treatment response of optic pathway glioma with positron emission tomography using alpha-[(11)C]methyl-L-tryptophan.
OBJECTIVE
To report the utility of positron emission tomography (PET) with alpha-[(11)C]methyl-L-tryptophan (AMT) for monitoring progression and response to treatment of an isolated optic pathway glioma (OPG) in a 16-year-old girl.


METHODS
Positron emission tomography scanning of the brain was performed 20 minutes after intravenous administration of AMT. The AMT-PET images were reconstructed and examined for tumor uptake of the tracer in correlation with coregistered magnetic resonance images.


RESULTS
The PET scan demonstrated increased uptake of AMT by OPG in a clinically symptomatic child whose magnetic resonance imaging (MRI) was inconclusive for morphological changes of the tumor. The tracer uptake was dramatically decreased on the images obtained after chemotherapy. Subsequently, AMT-PET revealed a new tumor lesion of increased AMT uptake when the patient developed vision problems and MRI showed no significant interval morphological changes. Significant vision improvement was observed after external beam radiotherapy for the newly identified tumor lesion.


CONCLUSIONS
Positron emission tomography with alpha-[(11)C]methyl-L-tryptophan may be useful for monitoring progression and response to treatment of OPGs, which needs to be further investigated in a prospective study of more patients, including those with neurofibromatosis.
Peng
Fangyu
F
The Carman & Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI 48201, USA. fpeng@med.wayne.edu
Juhasz
Csaba
C
Bhambhani
Kanta
K
Wu
Dafang
D
Chugani
Diane C
DC
Chugani
Harry T
HT
D000293:Adolescent; D002250:Carbon Radioisotopes; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D020339:Optic Nerve Glioma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D014364:Tryptophan / Q000031:analogs & derivatives*
D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; C020774:alpha-methyltryptophan; D014364:Tryptophan