Jens M. Edmund

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PURPOSE In radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, the information on electron density must be derived from the MRI scan by creating a so-called pseudo computed tomography (pCT). This is a nontrivial task, since the voxel-intensities in an MRI scan are not uniquely related to electron density. To solve the task,(More)
Radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, so-called MRI-only RT, would remove the systematic registration error between MR and computed tomography (CT), and provide co-registered MRI for assessment of treatment response and adaptive RT. Electron densities, however, need to be assigned to the MRI images for dose(More)
BACKGROUND MRI-only radiotherapy will eliminate the systematic registration errors introduced when transferring MRI information to the CT. However, challenges concerning the missing information on electron density, necessary for dose calculation and patient setup on bony anatomy are introduced. This study presents a possible statistical approach to(More)
In 116 diabetic eyes scheduled for vitreous surgery, the visual evoked potential (VEP) after flash stimulation was recorded prior to surgery. Latencies of the flash evoked potentials show a distribution suggestive of a Gaussian curve with an abnormal extension. Dividing the material into two groups based on a latency shorter or longer than 100 milliseconds(More)
PURPOSE In radiotherapy based only on magnetic resonance imaging (MRI), knowledge about tissue electron densities must be derived from the MRI. This can be achieved by converting the MRI scan to the so-called pseudo-computed tomography (pCT). An obstacle is that the voxel intensities in conventional MRI scans are not uniquely related to electron density.(More)
Radiotherapy based on magnetic resonance imaging as the sole modality (MRI-only RT) is an area of growing scientific interest due to the increasing use of MRI for both target and normal tissue delineation and the development of MR based delivery systems. One major issue in MRI-only RT is the assignment of electron densities (ED) to MRI scans for dose(More)
To determine whether or not the electrophysiological status of the eye can give information as to the result of vitreous surgery, the visual evoked potential to flash stimulation was measured prior to vitreous surgery. Seventy-four eyes were submitted to surgery. Latencies of flash evoked potentials showed a distribution suggestive of a Gaussian curve with(More)
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