Computed radiography

Abstract

In several medical centers computed radiography has almost completely replaced the use of conventional screen-film systems for general radiography. The aim of this paper is to explain the basic principles of the four most frequently numerical detectors used in the world, with emphasis on the phosphor plates, which are the most frequently used both in hospitals and by practitioners. The other two systems are based on a receptor with selenium. The fourth uses charged coupled device (CCD) detectors. The most important principles of digital processing are then described with concentration on unsharp mask filtering. In the future computed radiography will replace standard radiology and will create a system in medicine using the power of computers to archive--with more efficiency and less space--patient medical data. The transmission of data to workstations and the processing of this data is the topic of a new field in medicine.

Numerical estimation of carbonate rock properties using multiscale images

“…A preprocessing step based on histogram stretching and unsharp filtering procedures also helps to enhance edges and fine details in the 3D original microtomography images before the segmentation procedure (Sone et al 1991;Frija et al 1998). A preprocessing step based on histogram stretching and unsharp filtering procedures also helps to enhance edges and fine details in the 3D original microtomography images before the segmentation procedure (Sone et al 1991;Frija et al 1998).…”

“…In order to be able to numerically simulate the rock properties, we need, first, to separate the porous and solid phases in the 3D digital images using a segmentation technique. A preprocessing step based on histogram stretching and unsharp filtering procedures also helps to enhance edges and fine details in the 3D original microtomography images before the segmentation procedure (Sone et al 1991;Frija et al 1998). Several image segmentation algorithms can be found in the literature based on manual, semi-automatic or fully automatic approaches (Meyer and Beucher 1990;Chao et al 2009).…”

Evaluation of body geometry and symmetry for adolescent idiopathic scoliosis with 3D body scanning system

“…However, the use of conventional radiography exposes children who are still growing to additional radiation, which is a health risk (Bagnall et al , 2009). Computed radiography (CR), which uses imaging plates instead of film cassettes, has a proven number of advantages over conventional radiography; yet, it still exposes patients to high levels of radiation (Frija et al , 1998). There is an X-ray imaging system that provides an overall enhanced image quality with reduced radiation as compared to CR (Deschenes et al , 2010), which is an ultrasound imaging system and has been successfully used to examine abnormal spines.…”