Abstract
Background MRI has shortcomings in differentiation between tumor tissue and post-therapeutic changes in pretreated brain tumor patients.
Patients We assessed 22 static FET-PET/CT-scans of 17 pediatric patients (median age 12 years, range 2–16 years, ependymoma n=4, medulloblastoma n=4, low-grade glioma n=6, high-grade glioma n=3, germ cell tumor n=1, choroid plexus tumor n=1, median follow-up: 112 months) with multimodal treatment.
Method FET-PET/CT-scans were analyzed visually by 3 independent nuclear medicine physicians. Additionally quantitative FET-Uptake for each lesion was determined by calculating standardized uptake values (SUVmaxT/SUVmeanB, SUVmeanT/SUVmeanB). Histology or clinical follow-up served as reference.
Results Static FET-PET/CT reliably distinguished between tumor tissue and post-therapeutic changes in 16 out of 17 patients. It identified correctly vital tumor tissue in 13 patients and post-therapeutic changes in 3 patients. SUV-based analyses were less sensitive than visual analyses. Except from a choroid plexus carcinoma, all tumor entities showed increased FET-uptake.
Discussion Our study comprises a limited number of patients but results corroborate the ability of FET to detect different brain tumor entities in pediatric patients and discriminate between residual/recurrent tumor and post-therapeutic changes.
Conclusions We observed a clear benefit from additional static FET-PET/CT-scans when conventional MRI identified equivocal lesions in pretreated pediatric brain tumor patients. These results warrant prospective studies that should include dynamic scans.
Dosimetric consequences of rotational errors in radiation therapy of pediatric brain tumor patients
