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EJNMMI Research
Fig. 1 | EJNMMI Research

Fig. 1

From: Optimization of diagnostic performance for differentiation of recurrence from radiation necrosis in patients with metastatic brain tumors using tumor volume-corrected 11C-methionine uptake

Fig. 1

Imaging of a 75-year-old woman who underwent gamma knife radiosurgery (GKR) at a dose of 18 Gy for metastatic brain tumor that originated from lung adenocarcinoma. a T1-weighted MR image with gadolinium enhancement showing contrast-enhanced lesion in the right frontal lobe (arrow). b 11C-MET PET image showing mild focal tracer uptake corresponding to enhanced lesion on MR image (arrow). c Metabolic tumor volume (MTV) was 0.156 cm3 (arrow). T/N ratio was 1.29, which was lower than the non-corrected cutoff value (1.61) but more than the MTV-corrected cutoff value (1.23). d This lesion was determined as recurrence by definition, the size of which significantly decreased after repeated GKR over 4 months as observed in a follow-up MR image (arrow)

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