OBJECT Where no society-based or manufacturer guidance on radiation limits to neuromodulation devices is available, this research provides the groundwork for neurosurgeons and radiation oncologists who rely on the computerized treatment plan clinically for cancer patients. The focus of the article is to characterize radiation parameters of attenuation and scatter when an incident therapeutic x-...

A system for cone-beam computed tomography (CBCT) based on a flat-panel imager (FPI) is used to examine the magnitude and effects of x-ray scatter in FPI-CBCT volume reconstructions. The system is being developed for application in image-guided therapies and has previously demonstrated spatial resolution and soft-tissue visibility comparable or superior to a conventional CT scanner under condit...

This chapter discusses the module for determining an object's true gray levels. To compute the true gray levels of an object of interest requires the removal of the overlapping background effects. This problem is quite complex and takes several steps to be resolved. First in Section 5.1, it will be shown that an n-object-overlapping problem can always be simplified to a two-object-overlapping p...

Conventional radiography only provides a measure of the X-ray attenuation caused by an object; thus, it is insensitive to other inherent informative effects, such as refraction. Furthermore, conventional radiographs are degraded by X-ray scatter that can obscure important details of the object being imaged. The novel X-ray technology diffraction-enhanced imaging (DEI) has recently allowed the v...

We have developed an object-based linear algebra package, currently with emphasis on sparse Krylov methods, driven primarily by needs of the Los Alamos National Laboratory parallel unstructured-mesh casting simulation tool Telluride. Support for a number of sparse storage formats, methods, and preconditioners have been implemented, driven primarily by application needs. We describe our object-b...

Introduction: Scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. Accurate estimation of scatter in projection data of SPECT is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. Methods: The objective of this paper is to develop and validate a scatter correction technique ...

Detection of moving objects in a video stream received from a moving camera is difficult computer vision task, because the motion of the camera blends with the motion of the objects in the scene. In order to tackle this problem, we propose a method based on optical flow calculation and Delaunay triangulation. Given a sequence of frames, firstly, we extract the corner feature points using ORB al...

Polycapillary x-ray optics provide an innovative new way to control x-ray beams. Placing these optics after the object to be imaged provides very efficient rejection of Compton scatter, while allowing image magnification without loss of resolution, image demagnification, or image shaping to match with digital detectors. Measured scatter rejection optics had primary transmissions greater than 50...

Patient dose reduction in C-arm computed tomography by volume-of-interest (VOI) imaging is becoming an interesting topic for many clinical applications. One limitation of VOI imaging that remains is the truncation artifact in the reconstructed 3-D volume. This artifact can either be a cupping effect towards the boundaries of the field-of-view (FOV) or an offset in the Hounsfield values of the r...