METABOLIC IMAGING
PET [11C]Methionine (MET)
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The highest uptake is observed in anaplastic oligodendrogliomas WHO grade III
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LGG are better detected by aminoacid tracers due to increased uptake in
the absence of blood-
brain barrier damage
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LGG: useful for differentiation from nonntumorous lesions, detection of recurrences, indication of
progressing disease
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Can differentiate better between Recurrent tumour and Radiation Necrosis with high
sensitivity and specificity (~75%): necrosis and glioses after therapy show a
reduction of ammoniated uptake in contrast to recurrent and residual tumour growth
.
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Deactivation of aminoacid transport is a early sign of response to chemotherapy
(Galldicks N et al Mol Imaging 2010). PET responders with a decrease of tumour
brain/ratio of >10% had a significant longer TTP and OS than patient with increase
tracer uptake after RT and CHT in GBM.