Evaluation of Tc99m-glucoheptonate for SPECT functional imaging of medulloblastoma.

ABSTRACT

OBJECTIVES: Functional imaging of medulloblastoma using SPECT has been a difficult problem as this tumour does not concentrate conventional brain tumour imaging radiopharmaceuticals. This study aimed to evaluate Tc99m-glucoheptonate as a "brain tumour-seeking" radiopharmaceutical for functional imaging of medulloblastoma. METHODS: Tc99m-glucoheptonate brain SPECT was performed in 27 patients with medulloblastoma after radiation therapy and with clinical suspicion of tumour recurrence. Histological verification was obtained within 7 days in patients with a SPECT diagnosis of tumour recurrence. Patients with a SPECT diagnosis of post-radiation gliosis were clinically observed for a minimum period of one year after the SPECT study. RESULTS: Fourteen patients had increased radiotracer uptake in the primary tumour bed, suggesting tumour recurrence. Histopathology confirmed viable medulloblastoma in all cases. Thirteen patients had no increased tracer uptake in the primary tumour bed, suggesting post-radiation gliosis. They all had a clinical course consistent with post-radiation gliosis. CONCLUSION: Tc99m-glucoheptonate is an ideal SPECT tracer for functional evaluation of medulloblastoma. SPECT utilising Tc99m-glucoheptonate is a reliable diagnostic modality to differentiate tumour recurrence from post-radiation gliosis in patients with medulloblastoma.