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PURPOSE Methyl-[11C]L-methionine ([11C]MET) positron emission tomography (PET) in brain tumors reflects amino acid transport and has been shown to be more sensitive than magnetic resonance imaging in stereotactic biopsy planning. It remains unclear whether the increased [11C]MET uptake is limited to solid tumor tissue or even detects infiltrating tumor(More)
PURPOSE Solid and necrotic brain tumors respond to radiosurgery, although necrotic lesions often contain a significant proportion of hypoxic cells which cannot become reoxygenated during the short overall treatment time of single dose application. In addition to the direct cytotoxic action, delayed vascular occlusion followed by ischemic tumor cell death(More)
Stereotactic radiosurgery with an adapted linear accelerator (linac-SRS) is an established therapy option for brain metastases, benign brain tumors, and arteriovenous malformations. We intended to investigate whether the dosimetric quality of treatment plans achieved with a CyberKnife (CK) is at least equivalent to that for linac-SRS with circular or(More)
Purpose: Methyl-[C]L-methionine ([C]MET) positron emission tomography (PET) in brain tumors reflects amino acid transport and has been shown to be more sensitive than magnetic resonance imaging in stereotactic biopsy planning. It remains unclear whether the increased [C]MET uptake is limited to solid tumor tissue or even detects infiltrating tumor parts.(More)
OBJECTIVE AND IMPORTANCE To demonstrate the usefulness of positron emission tomography-magnetic resonance imaging (MRI) coregistration for differentiation of radiation necrosis and recurrent tumor in stereotactic planning. CLINICAL PRESENTATION T1-weighted MRI scans of a 43-year-old woman revealed a contrast-enhancing lesion 4 years after open removal of(More)
We have developed a densitometric method for measuring the isocentric accuracy and the accuracy of marking the isocentre position for linear accelerator based radiosurgery with circular collimators and room lasers. Isocentric shots are used to determine the accuracy of marking the isocentre position with room lasers and star shots are used to determine the(More)
OBJECTIVE The immediate effects of deep brain stimulation (DBS) on subcortical neurons of its target region are controversial. METHODS We measured the regional normalized resting cerebral metabolic rate of glucose (nCMRGlc) with 18-fluorodeoxyglucose (FDG) and PET in 12 patients with Parkinson disease (PD) and bilateral DBS of the subthalamic nucleus(More)
PURPOSE Head and neck tumors are often treated by a multiple-field technique, using a combination of opposing photon fields and electron beams in order to stay within the limit of the myelon tolerance dose. Dose inhomogeneities at field margins must be minimalized to avoid an increased rate of local recurrences or late complications. METHODS A polystyrene(More)
A new approach is presented for unwarping geometrical distortions in echo planar imaging (EPI)-based statistical parametrical maps (SPM). With the developed method, a substantial reduction of geometrical distortions in the order of 5-15 mm down to a residue of approximately 1-2 mm was possible, thus allowing reliable activation localization and, hence,(More)
AIMS To evaluate the efficacy of interstitial brachytherapy using (125)iodine ((125)I) seeds for the treatment of recurrent multimodal treated medulloblastoma. MATERIALS AND METHODS Between September 1989 and August 2009, 12 patients (female:male=3:9, median age 19 years, range 7-55 years) with 23 recurrent medulloblastomas underwent interstitial(More)