Digital X-Rays

Ben Frein

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HISTORY

 

Developed in 1895 by physicist Wilhelm Roentgen, the X-ray allow structures beneath the skin to become completely visible. What makes this possible is the fact that X-rays travel in waves and can enter solid objects where they are either absorbed or continue to pass through depending on the density. The resulting energy is then recorded on a film to be developed with dense areas appearing very white and less dense areas dark. This has been the standard for over 100 years; however, the digital X-ray is now becoming more inexpensive, popular, and simple to use.

 

HOW IT WORKS

 

Digital imaging techniques came to X-ray in the 1980s when analog to digital converters and computers were also adapted to conventional fluoroscopic image intensifier systems. Just as digital recordings on dvd's and compact disks sound better than their analog predecessors, digital X-rays often look sharper and cleaner than the analog version. Eventually the majority of film cassette/film screen systems will be replaced by digital X-ray detectors. With a digital radio-graph, the film is replaced with a flat electronic pad or sensor. The pad collects the X-ray energy in the same way as the film, however instead of being developed, the image is electronically sent to a computer where the image appears on a screen. From here the image can then be viewed, stored, sent to another machine, or printed out. "Many observers have hailed it as the most significant breakthrough in X-ray imaging in the last 25 years, referring to it as 'the New Modality' " (GE Healthcare)

 

	Fig. 1a: In a conventional, digitized R&F imaging chain, the signal degradation that occurs with each component consumes more than 60% of the original x-ray signal.
	Fig. 1b: A digital detector replaces all these components, allowing the user to preserve more than 80% of the original signal â.. and to further enhance that signal automatically or explicitly.

 

The above images from GE Healthcare show that using conventional methods, less than 40% of the original image information is retained for image production, while using an all digital method captures more than 80% of the image information. This allows the information to be used in a much wider range of post-processing tools, some of which may be automated in the near future. The digital technology converts images into digital images at the detector itself by creating a matrix of pixels with each pixel digitally coded. Once acquired, the image is no longer susceptible to noise.

 

BENIFITS

 

In addition to the clearer, more reliable images produced, digital X-rays also give you much more flexibility in what you do with the images. One of the most popular advantages is a process called subtraction radiography. In subtraction radiography, a radio-graph can be digitally compared to previous radio-graphs. All of the similarities are subtracted out and the result is a clear image of anything which has changed. This will have a huge impact on diagnostics, as very tiny changes which were unnoticeable with the naked eye can now be caught and treated much earlier. Other popular and future applications which will interact with digital X-rays include: computer-aided detection, tomosynthesis, angiography, dual-energy imaging, and low-dose fluoro positioning.

 

Another great benefit of using all digital X-ray technology is that a digital radio-graph requires 75-80% less radiation than a standard radio-graph would. The digital X-rays can also easily be enhanced, false colored, rotated, cropped, and manipulated in many other ways. Digital X-rays pose a significant financial benefit as they require little space for storage and no labor expenses for retrieval and filing. After the initial equipment costs, which can run very high, operating costs are almost nothing. There is no cost of film, processing equipment, chemicals, etc. The only cost is that of maintaining the systems, which are currently being built very durable and reliable.

 

Digital X-rays are easy to send, and many specialists could all view the same high quality original simotaniously. Unlike standard film X-rays, the quality of a digital X-ray will never degrade.

(X-ray Courtesy of Dr. Patrick Carney, DDS)

 

DIFFERENT APPROACHES