Saccades, elicited by an identical visual stimulus in repeated trials, exhibit a certain amount of amplitude and direction scatter. The present paper illustrates how this scatter may be used to discern various properties of the subsystem that determines the metrics of a saccade. It is found in humans that scatter along the eccentricity axis is consistently more pronounced than along the directi...

Scatter correction is an important factor in single photon emission computed tomography (SPECT). Many scatter correction techniques, such as multiple-window subtraction and intrinsic modeling with iterative algorithms, have been under study for many years. Previously, we developed an efficient slice-to-slice blurring technique to model attenuation and system geometric response in a projectorhac...

Well-known radar scattering mechanisms are Rayleigh scattering (incoherent particle scattering), and clear-air scattering (coherent air scattering). This article discusses the importance in clouds of these two mechanisms compared to a third scattering mechanism: coherent particle scattering, which is caused by spatial variations in the liquid water content of the clouds. We will argue that for ...

Basic dosimetric properties of 6 MV and 18 MV photon beams from a Varian Clinac 21EX accelerator operating without the flattening filter have been measured. These include dose rate data, depth dose dependencies and lateral profiles in a water phantom, total scatter factors and transmission factors of a multileaf collimator. The data are reviewed and compared with measurements for the flattened ...

Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany Despite promising advances, attenuation correction of PET data remains challenging in PET/MRI. Known approaches to estimating attenuation maps from PET emission data take into account only true coincidences and fail to completely determine the attenuation map...

A three-dimensional reconstruction method for simultaneous compensation of attenuation, scatter and distance-dependent detector response for single photon emission computed tomography is described and tested by experimental studies. The method determines the attenuation factors recursively along each projection ray starting at the intersected source voxel closest to the detector. The method sub...

The requirements for shielding a treatment vault with a Varian Clinac 2100 medical linear accelerator operated both with and without the flattening filter were assessed. Basic shielding parameters, such as primary beam tenth-value layers (TVLs), patient scatter fractions, and wall scatter fractions, were calculated using Monte Carlo simulations of 6, 10 and 18 MV beams. Relative integral target...

In this paper, a supervised feature extraction method, named orthogonal discriminant projection (ODP), is presented. As an extension of spectral mapping method, the proposed algorithm maximizes the weighted difference between the non-local scatter and the local scatter. Moreover, the weights between two nodes of a graph are adjusted according to their class information and local information. Ex...