Computed radiography

You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.

It has been suggested that this article or section be merged into Digital radiography. (Discuss)

Contents 1 Differences from Direct Radiography 2 Imaging plate 3 Industrial applications 3.1 Advantages 3.2 Disadvantages 4 References 5 Acknowledgement and Attribution Regarding Sources of Content

Computed Radiography (CR) uses very similar equipment to conventional radiography except that in place of a film to create the image, an imaging plate is used. Hence, instead of taking a film into a darkroom for developing in chemical trays, the imaging plate is run through a computer scanner to read and digitize the image. The image can then be viewed and enhanced using software that has functions very similar to conventional image-processing software, such as contrast, brightness, and zoom.

Differences from Direct Radiography

Computed radiography is commonly distinguished from Direct Radiography (DR). In the same way that a CR system requires a short burst of radiation, so does a DR system. The difference is that on exposure a DR system will almost instantly display the image on the screen in front of the radiographer, therefore removing any need for processing. Post production can of course be performed on DR images in the same way that CR images can.

This is NOT to be confused with Fluoroscopy, where there is a continuous beam of radiation, and the images appear on the screen like on a TV. This is the system most people are familiar with, as this is what is used in airport security systems.

Imaging plate

The imaging plate contains photostimulable storage phosphors, which store the radiation level received at each point in local electron energies. When the plate is put through the scanner, a scanning laser beam causes the electrons to relax to lower energy levels, emitting light that is measured to compute the digital image. Imaging plates can be re-used thousands of times if they are handled carefully, although handling under industrial conditions may result in damage after a few hundred uses. An image can be erased by simply exposing the plate to a room-level fluorescent light, and the plate is then ready for re-use. In the software, the scanned image is encrypted so that the original data is kept secure and can not be tampered with.

Industrial applications

Common applications for computed radiography include:

• corrosion surveys on pipes, often through insulation;
• Examination of valves for erosion;
• Information shots on industrial components; e.g. checking to see if a valve is closed properly, or checking for obstructions in valves and pipes;
• Examination of boiler water walls.

Radiographic testing using computed radiography has pros and cons:

Advantages

• No film or chemicals; instead a computer is used
• Image available faster; commonly one minute instead of seven minutes, as with conventional radiography
• By adjusting image brightness, a wide range of thicknesses can be examined in one shot, unlike conventional radiography, which requires a different exposure time for each thickness in a component. Computed radiography thus requires fewer re-shots due to under- or over-exposure.
• Images can be stored on disk or transmitted for off-site review.

Disadvantages

• Due to the high cost of the CR equipment and the training required to operate the CR systems, pricing is typically higher when compared to traditional film radiography. In medical situations though, the break even point with not having to use chemicals and have a darkroom reduce the ongoing cost considerably.

References

• Computed Radiography in NDT Applications
• Digital Applications of Radiographyit:radiografia computerizzata

WikiDoc Help Menu Quick Start.. Get Started Here! How to Login How to Search Pages How to Start a New Page How to Edit a Page Cheat Sheet Editing basics Learning Basic Formatting How to make Links in WikiDoc & to External Sites How to Make Lists How to Ignoring Formatting Adding References or Footnotes to Articles Tracking Changes You Have Made How to Put an Article Into a Category When Multiple Topics Should Go To The Same Page (MI, Acute MI, AMI) Using Redirection Advanced editing How to Make Tables How to Insert Images and Other Media How to Add Video Help:How to Make Columns Web Colors How To Make Templates How to Move Pages Inserting Dynamic Dates and Times Inserting WikiDoc Statistics Editing the Table of Contents Communicating your edits Let others know what you changed: The importance of Edit Summaries Minor Edits Edit Conflicts Help Videos You Can Watch Getting Started Video

Acknowledgement and Attribution Regarding Sources of Content

Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .