Title : Pre-irradiation tumour volumes defined by MRI and dual time-point FET-PET for the prediction of glioblastoma multiforme recurrence: a prospective study
Comparison of pre-treatment MRI and dual time-point 18F-fluoroethylthyrosine-PET (FET-PET)-based target volumes with patterns of primary glioblastoma multiforme failure following radiotherapy with temozolomide is done. Established that FET-based tumor volumes measured 10 minutes after radionuclide injection were, on average, larger than tumor volumes measured 60 minutes after radionuclide injection. PET volumes were significantly larger than corresponding MRI-based volumes. MRI and FET concordance for the identification of glioblastoma GTVs was poor (mean uniformity index 0.4). 74% of failures were inside primary PET volumes, with no solitary progressions inside the MRIdefined margin +20 mm but outside the PET-defined area detected. Therefore conclude that the size and geometry of GTVs differed in the majority of patients, PET volume depends on time after radionuclide injection, and FET-PET better defined failure site than MRI alone.