Effect of 11C-methionine-positron emission tomography on gross tumor volume delineation in stereotactic radiotherapy of skull base meningiomas.
OBJECTIVE
To evaluate the effect of trimodal image fusion using computed tomography (CT), magnetic resonance imaging (MRI) and (11)C-methionine positron emission tomography (MET-PET) for gross tumor volume delineation in fractionated stereotactic radiotherapy of skull base meningiomas.


METHODS
In 32 patients with skull base meningiomas, the gross tumor volume (GTV) was outlined on CT scans fused to contrast-enhanced MRI (GTV-MRI/CT). A second GTV, encompassing the MET-PET positive region only (GTV-PET), was generated. The additional information obtained by MET-PET concerning the GTV delineation was evaluated using the PET/CT/MRI co-registered images. The sizes of the overlapping regions of GTV-MRI/CT and GTV-PET were calculated and the amounts of additional volumes added by the complementing modality determined.


RESULTS
The addition of MET-PET was beneficial for GTV delineation in all but 3 patients. MET-PET detected small tumor portions with a mean volume of 1.6 +/- 1.7 cm(3) that were not identified by CT or MRI. The mean percentage of enlargement of the GTV using MET-PET as an additional imaging method was 9.4% +/- 10.7%.


CONCLUSIONS
Our data have demonstrated that integration of MET-PET in radiotherapy planning of skull base meningiomas can influence the GTV, possibly resulting in an increase, as well as in a decrease.
Astner
Sabrina T
ST
Department of Radiation Oncology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany. sabrina.astner@gmx.de
Dobrei-Ciuchendea
Mihaela
M
Essler
Markus
M
Bundschuh
Ralf A
RA
Sai
Heitetsu
H
Schwaiger
Markus
M
Molls
Michael
M
Weber
Wolfgang A
WA
Grosu
Anca-Ligia
AL
D000328:Adult; D000368:Aged; D002247:Carbon Isotopes; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008579:Meningioma; D008715:Methionine; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D016634:Radiosurgery / Q000379:methods*; D019292:Skull Base Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome
D002247:Carbon Isotopes; D019275:Radiopharmaceuticals; D008715:Methionine