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Effect
of radiotherapy on brain glucose metabolism in patients operated on
for low grade astrocytoma
M Bruehlmeier, U
Roelcke, B Amsler, K H Schubert,
O Hausmann, K von Ammon, E W
Radü, O Gratzl, C Landmann,
K L Leenders
PET Program, Paul Scherrer
Institute, CH-5232 Villigen, Switzerland [M.B., U.R., K.L.L.],
Department of Radiotherapy [B.A., K.H.S., C.L.], Department of
Neurosurgery [O.H., O.G.], Department of Neuroradiology, University
Hospital, CH-4031 Basel, Switzerland [E.W.R.], Department of
Neurosurgery [K.v.A.], Department of Neurology, University Hospital,
CH-8091 Zürich, Switzerland [K.L.L.]. Correspondence to: Dr M
Bruehlmeier, PET Program, Paul Scherrer Institute, CH-5232 Villigen,
Switzerland. Telephone 0041 56 310 36 84; fax 0041 56 310 31 32;
email: Matthias.Bruehlmeier{at}psi.ch. Received
30 December 1997 and in revised form 6 August 1998; Accepted 29
October 1998.
Objective. To
assess the effect of postoperative radiotherapy on brain glucose
metabolism (CMRGlu) of operated patients with low grade astrocytomas.
Methods. PET and 18F-fluorodeoxyglucose
was used to measure absolute CMRGlu in patients with fibrillary
astrocytoma (WHO II) of the frontal lobe, who did (n=7) or
did not (n=12) receive radiotherapy subsequent to first
debulking tumour resection.
In addition, statistical parametric mapping (SPM95) was
applied to assess the pattern of relative CMRGlu associated
with the frontal tumour.
Data were compared with 12 healthy controls.
Results. A global
reduction of absolute CMRGlu was found when either patients with or
without radiotherapy were compared with controls (ROI
analysis).
Brain areas of relative CMRGlu reduction
were found in the brain ipsilateral and contralateral to
the tumour, comparing both patient groups with controls by
SPM ("tumour diaschisis effect").
Superimposed, absolute CMRGlu in the
contralateral frontal, parietal, occipital cortex as well
as in the white matter was on average 17% lower in patients
receiving radiotherapy than in patients who did not.
Conclusions. The data
discriminate a tumour effect from a radiotherapy effect, and support
the view of adverse effects of radiotherapy on brain not
directly involved by tumour.
Keywords: low grade astrocytoma;
brain glucose metabolism; radiotherapy
© 1999 by Journal of Neurology,
Neurosurgery, and Psychiatry
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