Background. We studied the use of
201Thallium SPECT and L-[1-
11C]-tyrosine PET in patients with a primary glioblastoma multiforme treated with
192Ir brachytherapy after surgery and external beam radiation therapy. We hypothesised that the patients most likely to benefit
from further surgery after deterioration would be those with radiation necrosis and would be recognised by a negative emission
tomography scan.
Methods. Twenty-one patients underwent 201Thallium SPECT performed before brachytherapy, and this was repeated in 19 patients when recurrence was suspected. Nine patients
also underwent a PET scan at the same time. Nine patients underwent a second operation.
Findings. SPECT and PET were highly concordant concerning the prediction of radionecrosis and/or tumour recurrence. Repeat surgery
did not lead to a significant increase in survival. There was no significant association between the duration of survival
and tumour-to-background ratio but the number studied was small. Both SPECT and PET showed highly active lesions, which were
proved to be recurrent tumour by clinical and histological follow-up.
Conclusion. Although PET and SPECT are both highly sensitive in detecting active tumour tissue, emission tomography was not clinically
valuable in the investigation of patients with a primary glioblastoma treated with brachytherapy.
Keywords: Brachytherapy; glioblastoma multiforme; 192Iridium; 201Thallium SPECT; L-[1-11C]-tyrosine PET; survival.
Correspondence: Radboud W. Koot, Department of Neurosurgery J-11-85, Leiden University Medical Centre, PO Box 9600, 2300 RC
Leiden, The Netherlands.