In emission tomography, images are usually represented by regular grids of voxels or overlapping smooth image elements (blobs). Few other image models have been proposed like tetrahedral meshes or point clouds that are adapted to an anatomical image. This work proposes a practical sparse and continuous image model inspired from the field of parametric density estimation for Gaussian mixture mod...

Novel algorithms in the field of X-ray imaging are commonly evaluated on simulation software first, before they are implemented on a clinical scanner in order to test their performance in a very controlled setup. This reduces patient dose and facilitates the development of new approaches and methods. In recent years, range imaging applications were established in the field of medical imaging. R...

The 3D reconstruction of cardiac vasculature, e.g. the coronary arteries, using C-arm CT (rotational angiography) is an active and challenging field of research. There are numerous publications on different reconstruction techniques. However, there is still a lack of comparability of achieved results for several reasons: foremost, datasets used in publications are not open to public and thus ex...

introduction: in diagnostic and therapeutic procedures, dosimetric studies are performed on the dosimetric systems in order to comply the radiation safety standards. monte carlo methods are used due to the high complexity and cost of patient-specific phantom construction. the high complexity of the digitized phantoms greatly increases the time and computational task of the monte carlo calculati...

This paper1 presents an architecture to meet the needs for authentication and authorization in Grid based component systems. While Grid Security Infrastructure (GSI) [1] is widely accepted as the standard for authentication on the Grid, distributed authorization is still an open problem being investigated by various groups [2],[3],[4]. Our design provides authentication and fine-grained authori...

Introduction and aim: In SPECT imaging, the finite spatial resolution of the imaging system leads to a blurring of the reconstructed image. Consequently, counts originating from each point in the source distribution will be spread out over a volume in the reconstructed image, leading to spill-over of counts between different structures and distortion of the apparent activity concentration. This...

Background: Since tumors located in thorax region of body mainly move due to respiration, in the modern radiotherapy, there have been many attempts such as; external markers, strain gage and spirometer represent for monitoring patients’ breathing signal. With the advent of fluoroscopy technique, indirect methods were proposed as an alternative approach to extract patients’ breathing signals...

background: the purpose of this study is to fabricate inexpensive in-house low cost homogeneous and heterogeneous human equivalent thorax phantom and assess the dose accuracy of the treatment planning systems (tps) calculated values for different lung treatment dosimetery. it is compared with thermoluminescent dosimeter (tld) measurement. materials and methods: homogeneous and heterogeneous tho...

Purpose Dual-energy computed tomography (DECT) is highly promising for material characterization and identification, whereas reconstructed material-specific images are affected by magnified noise beam-hardening artifacts. Although various DECT decomposition methods have been proposed to solve this problem, the quality of decomposed still unsatisfactory, particularly in image edges. In study, a ...