Table of Contents
International Journal of Molecular Imaging
Volume 2012 (2012), Article ID 412585, 7 pages
http://dx.doi.org/10.1155/2012/412585
Clinical Study

Contribution of 18F-Fluoro-ethyl-tyrosine Positron Emission Tomography to Target Volume Delineation in Stereotactic Radiotherapy of Malignant Cranial Base Tumours: First Clinical Experience

1Department of Radiation Oncology, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
2Department of Nuclear Medicine, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
3Department of Radiation Oncology, Klinikum Frankfurt (Oder), Müllroser Chaussee 7, 15236 Frankfurt, Germany

Received 24 April 2012; Revised 16 September 2012; Accepted 30 September 2012

Academic Editor: Habib Zaidi

Copyright © 2012 Reinhold Graf et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Increased amino acid uptake has been demonstrated in intracerebral tumours and head and neck carcinomas of squamous cell origin. We investigated the potential impact of using 18F-fluoro-ethyl-tyrosine (18F-FET)-PET/CT in addition to conventional imaging for gross tumour volume (GTV) delineation in stereotactic radiotherapy of skull base tumours. The study population consisted of 14 consecutive patients with cranial base tumours (10 with squamous cell histology, 4 others). All patients underwent a FET-PET/CT examination in addition to contrast-enhanced CT and 11 patients underwent MRI. All tumours and histologic types showed increased FET uptake. The GTV was defined by all voxels showing hyperintensity in MRI or CT (GTVMRI/CT) or enhancement in PET (GTVPET), forming a GTVcomposite that was used for the initial treatment fields. An additional volume of infiltrative growth outside the GTVMRI/CT of about 1.0 ± 2 cm3 (5% of the conventional volume) was demonstrated by FET-PET only (GTVPETplus) with significant enlargement (>10% of GTVMRI/CT) in three patients. From existing data, we found correlation between cellular density and the standardized uptake value (SUV) of FET. We were able to substantially reduce the volume of escalated radiation dose (GTVboost) by 11 ± 2 cm3 (24%) of the conventional volume.