Consider it akin to dramatic alignment of the stars propelling adoption of digital radiography systems. It was only a matter of time until this technology began grabbing a toehold in radiology departments, once CT, MR and PET systems were installed, and institutions obtained the necessary image management capabilities of PACS.
With general radiography lagging behind in the analog world, true efficiency was illusive. In the beginning, many institutions turned to computed radiography because of the ease of a retrofit into their existing x-ray systems, and the cost of CR was easier to justify. However, as DR technology evolved — with increased speed of image acquisition leading to improvements in throughput and better image quality — many hospitals and imaging centers have considered DR systems as an answer to their digital imaging needs in general radiology, orthopedics and trauma centers. For the most part, DR is a replacement technology for analog rooms as well as new x-ray rooms. CR, in contrast, tends be installed based on the need to retrofit an existing department to digital and meet new workflow needs.
Industry analysts from Frost & Sullivan released a report in January that suggests digital x-ray systems adoption has been increasing since 2002. Overall, the marketplace estimates the DR growth rate at about 5 percent annually. As these systems improve their capabilities and cost considerations decline, Frost & Sullivan deems the digital x-ray market to be vibrant with opportunities for growth robust. Currently CR outsells DR at a ratio of 10:1 with a reported 602 DR units sold in 2005 as compared to 5,000 CR units during the same time frame. Industry estimates place CR growth in North America between 15 and 30 percent annually, which has slowed from prior years largely due to market saturation, which is estimated at about 50 percent.
Although CR units are significantly less expensive than DR — the average DR system ranges from $400,000 to $500,000 range, while CR systems typically sell for $200,000 to $300,000 — there are drawbacks in the speed of image display due to the necessary steps in accomplishing CR studies. With DR, the image is captured and displayed within seconds on a workstation.
Currently, many radiology departments in hospitals and free-standing imaging centers must contend with a combination of DR, CR and analog systems. Once these facilities are able to fully integrate digital imaging across all modalities, they anticipate increased efficiency will be enabled.
J. Anthony Seibert, PhD, professor of radiology at the University of California at Davis anticipates a paradigm shift away from CR towards DR. With two types of detectors, direct and indirect, and pros and cons to each type, he explains that the new charged coupled device (CCD) detectors have made inroads towards adoption of DR technology.
"If you asked physicists five years ago about the possibility of having a useful CCD detector in diagnostic radiology, they would have said it couldn't happen because of a phenomenon called a secondary quantum sync that occurs at a point in the cascading of the signal from the acquisition of the X-ray through various processing steps," he explains. Technologic breakthroughs, including the use of Cesium iodide as a structured phosphor as opposed to a non-structured screen produces better light capture efficiency, and thereby secondary quantum sync does not occur. Additionally, improvements in the lens systems have been developed. "Those two phenomena coupled together have made the CCD camera-based DR system fairly functional and dose efficient."
In describing the Imaging Dynamics Corporation Xplorer DR system in particular, Seibert notes that a 16 million pixel CCD camera (4096 X 4096 pixels) reflects back to a large area simulator resulting in a spatial resolution sampling of about 100 microns. "So for a large field of view DR system, it has high sampling."
Meanwhile, in the world of DR, systems offer increased image resolution with reduced radiation dose, and attractive price points. Innovative enhancements such as automated functionality have improved efficiency and throughput while adding to the ease of use for technologists. Such advances have increased the attractiveness of DR for sure.
Automated functionality = improved efficiency
Don Schreiner, BA, MBA, chief operating officer for Rockford Orthopedic Associates in Illinois, describes their evolution from one Swissray Modulaire system to their