This CR study, a lateral projection of the lumbar spine, demonstrates standard processing of the vertebral bodies, interspaces, spinous processes and the lumbosacral junction. Image courtesy of iCRco.

Digital radiography, which comprises both computed radiography (CR) and direct radiography (DR), has gained strong market acceptance as a preferable alternative to screen-film x-ray. The reasons for this favorable reception vary, with perhaps the biggest driver being the growing demand from clinicians, patients and institutions for the digital diagnostic imaging record—accomplished via image information systems such as PACS and RIS.

DR systems utilize a variety of media to convert x-rays into digital images. Under the umbrella of DR are both direct and indirect detector technologies. Direct detector systems employ amorphous selenium, lead oxide, lead iodide, thallium bromide, or gadolinium mixtures. These materials act as a photoconductor that converts x-ray photons into an electrical charge, which is then converted into a digital image by an analog-to-digital converter. Indirect detector DR systems use charge-coupled device (CCD), phosphor, or amorphous silicon to record the x-ray photons, which are converted into an electrical charge and then converted into a digital image.

CR systems use an image plate of photostimuable phosphor crystals that replace traditional film in a cassette. When the plate is exposed to x-rays, the energy is absorbed and stored by the crystals. The cassette is placed in a CR reader, where the energy is released by exposing the plate to a laser beam. This light energy is collected by photomultipliers, converted to electrical charges, and then converted to a digital image.

Both CR and DR systems output a digital image on which quality control (QC) is generally performed by a technologist at a computer workstation, who then electronically sends the image to a physician for interpretation on a diagnostic workstation. On a functional level, a primary difference between the technologies is that CR requires media to be introduced into a reader, while DR does not.

Although DR systems are typically priced higher than CR systems, reimbursement for services conducted on either modality is equivalent. The Centers for Medicare & Medicaid Services (CMS) reimburses diagnostic x-ray services for its beneficiaries at the same price point regardless of the technology employed to obtain the image, whether it is screen-film, DR, or CR.

For a practice looking to incorporate digital radiography into its service line, this is a significant factor in the necessary calculations for the return on investment of this technology purchase—particularly in light of declining reimbursement rates from both government and private insurers.

According to market research firm Frost & Sullivan, the U.S. digital radiography market is steadily gaining greater presence in hospital and clinical settings. Because x-ray radiography constitutes nearly 60 percent of the images acquired in a radiology practice, acquiring and storing digital images is a necessity for administrators to control costs and increase workflow efficiency within their respective departments.

Although CR allows entry into the digital realm for a fairly reasonable cost, purchase price isn’t the only factor fueling its growth. An appealing feature of CR is its suitability for addition to equipment a hospital already owns.

“We’ve been able to use the x-ray systems we have in place without having to retrofit existing rooms,” says Cindy Klieman, radiology administrator at Port Huron Hospital in Port Huron, Mich.

Her 186-bed facility first deployed Fuji-film CR equipment in 1994 and she says they have been extremely pleased with the quality, value and versatility of the technology over the past 14 years.

“It’s a very reliable workhorse for all our general radiography requirements,” she says. “It’s easy to use, has been integrated into all our x-ray areas, and provides high-quality images.”

Both CR and DR have the capability to consolidate x-ray rooms, achieve greater throughput to meet high-volume needs, improve image quality and reduce retakes, help mitigate the problem of lost films, and be an integral part of the digital diagnostic imaging record.

“The CR product was the most effective way for us to take a step into the digital world,” says Richard Wendt, director of radiology at St. Anthony Hospital in Gig Harbor, Wash., part of the Franciscan Health System and the Denver-based Catholic Health Initiatives.

Wendt introduced the Konica-Minolta CR line to his department at St. Francis Hospital in Federal Way, Wash., and reported that it was a seamless transition.

“Our technologists were used to working with film cassettes, so the workflow didn’t have to change at all; between the cost and the workflow issue, those were the big reasons we chose to go with CR rather than changing our rooms out for DR,” he says.

Klieman noted that the technologists at Port Huron were equally happy with the deployment of CR.

“From a technologist perspective, the CR technology was received with open arms; everyone was very willing to stop going into the darkroom to process images,” she says. “All our technologists were thrilled with CR.”

Both Wendt and Klieman say they are pleased with the benefits of CR at their respective institutions—decreased repeat rates, increased throughput and productivity and better quality images.

In general, the basic radiographic principles for CR are the same as for conventional film-screen x-ray. There is a learning curve as systems move from conventional film to digital, but it wasn’t intensive or complicated, according to Wendt and Klieman.

Dose creep, where a technologist slightly increases radiation dose to acquire a “better” looking image, cropped up in some instances, the managers report. However, each CR manufacturer’s software system allows for a review of the technique used to acquire each exposure—which has allowed for dose creep to be detected and corrected with the offending technologist.

“We really honed our technique for sensitivity (S) value optimization,” Wendt says. “All the fine-tuning of our technique was done in consultation with our radiologists; it was a team effort devoted to turning out the best quality product at the lowest possible dose.”

Although film use has been significantly reduced, the managers confess that it hasn’t ceased completely. They both report that some referring physicians are simply more comfortable with film; thus they haven’t yet retired it completely and will print out exams on demand.

“Everyone adapts to technology at a different rate,” Klieman notes.

“We try not to print out film,” Wendt says. “For the majority of our referrers, we burn [images] out [on] CDs that incorporates a DICOM viewer on the disc so they can review the image. We also have web access available through our PACS if they want to review the images and report online.”

As capital budgets get tighter and credit facilities get leaner through the current economic downturn, more facilities may find CR technology an attractive option for their digital radiography requirements.

Regardless of the ultimate technology selection for digital radiography acquisition, deployment is a win for both patient and practice. Patients benefit from a faster image workflow that speeds diagnosis and hospitals achieve a digital distribution process that provides a more efficient imaging workflow, which can lead to increased revenues.