Mario Patino-Zarco MD, Presenter: Nothing to Disclose

Irma Soldevilla-Gallardo, Abstract Co-Author: Nothing to Disclose

Osvaldo Garcia-Perez MD, Abstract Co-Author: Nothing to Disclose

Enrique Estrada-Lobato MD, Abstract Co-Author: Nothing to Disclose

Current imaging techniques, such as MRI, CT, FDG-PET have a limited role in the follow-up evaluation of patients with primary brain tumours (PBT), usually they cannot make an appropriate differentiation between radiation changes and tumour recurrence, which is critical for patient survival. (18F) fluorothymidine (FLT) is a relatively novel radiotracer aimed to identify sites with increased cellular proliferation, typical of primary brain tumour recurrence, without the inconvenience of high uptake by the normal brain as in FDG PET.

18F-FLT PET/CT was performed in 8 patients treated (chemo-radiotherapy) for high grade primary brain tumours; all the patients had inconclusive MRI results on follow-up.

12 lesions where identified, 11 showed high FLT uptake, corresponding with tumour recurrence, 1 lesion had no FLT uptake and represented radiation necrosis. The average background/lesion ratio for the FLT positive sites was 11.9 (range 4-24) whereas the ratio for the FLT negative site was 1 (P: 0.001).

18F-FLT PET/CT is a promising imaging tool in the follow-up of patients with PBT, with highly specific findings that can differentiate radiation changes vs. tumour recurrence.

We recommend FLT-PET for imaging CNS tumors (primary or mestastatic), high background/lesion ratios make this technique the first choice for nuclear medicine imaging at our institution.

Patino-Zarco, M, Soldevilla-Gallardo, I, Garcia-Perez, O, Estrada-Lobato, E, Usefulness of 18F-FLT PET/CT in the Differential Diagnosis of Radiation Changes vs Tumour Recurrence in the Follow-up of Patients with Primary Brain Tumours.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010499.html