Vendors implement strategies for lowering cost of digital x-ray

October 31, 2001

Some developers of digital x-ray equipment are playing for time outside medical markets, hoping that revenue streams from applications such as nondestructive testing will help underwrite the costs of evolving and manufacturing radiology-quality

Some developers of digital x-ray equipment are playing for time outside medical markets, hoping that revenue streams from applications such as nondestructive testing will help underwrite the costs of evolving and manufacturing radiology-quality detectors.

“One of the biggest strategies in anyone’s flat-panel business is volume, because the panels are expensive to manufacture, and the facility that makes the receptor itself is expensive to operate,” said Chuck Blouir, marketing manager for Varian’s flat-panel business. “That means finding any and all niches to fit our products into.”

For Varian, nondestructive testing of PC boards represents a large and virtually untapped market. Every PC has several boards and each must be tested to ensure its integrity.

“It’s not easy with the technology that’s available today, but flat panels make it easier to do an in-depth analysis,” Blouir said. “The nondestructive testing market is not nearly as large as the medical market, but it is faster to adapt to new technology, simply because there isn’t the same need for clinical research. We take advantage of that.”

Another problem that has long plagued the detector market has been lengthy production timelines, something that vendors are acutely aware of and attempting to solve.

“Production of detectors has been a source of great concern in the marketplace over the past couple of years,” said Tim Stevener, director of digital radiography at Philips Medical Systems. “But we’ve more or less resolved that, and our detector delivery is at a substantially higher rate than it was at the beginning of the year. We are shipping a high volume of them every day.”

The amorphous silicon-based plates used by Philips in its Bucky Vision and Digital Diagnost dedicated chest unit, to be shown at the upcoming RSNA meeting, are manufactured by Trixell, a joint venture of Philips, Siemens, and Thomson Tubes Electroniques. The same technology is also being adapted by Infimed for its StingRay DR and Siemens’ Thorax FD and Multix FD.

Vendors agree that the high price of digital radiography equipment has been holding back market growth. The highest-profile, highest-tech versions, flat panels made from amorphous silicon and amorphous selenium, rely on electronic arrays that immediately transmit data to a network, archive, or workstation for display of the reconstructed image. These signals can be created either directly or indirectly. Electronic arrays made from amorphous selenium directly generate electrical impulses. Plates made from amorphous silicon register flashes of light produced when x-rays strike a thin coating of scintillation material made of cesium iodide. Both selenium- and silicon-based chips are akin to very large computer chips.

A key factor driving costs is the difficulty manufacturers have meeting the specifications for medical-grade silicon and selenium plates. The relatively low rate of adoption by end users doesn’t help. But these two technologies are not the only solutions available to buyers of medical systems. Increasingly, prospective customers are recognizing that alternatives such as charge-coupled device (CCD)-based systems and computed radiography (CR) have attractive qualities.

Flat-panel systems cost more than three times as much as CR systems, which average $100,000 for a basic configuration. As a result, many sites desiring to go digital have adopted CR for general radiographic needs.

Because CR systems record x-ray strikes on phosphor plates, they are among the least expensive options for facilities wanting to go digital, since these plates can be substituted for film buckys.

CCD systems offer a different low-cost possibility. Imaging Dynamics markets a turnkey digital radiography system and a retrofit package for film-based systems. Both are built around its own brand of CCD-based technology, according to Robin Winsor, chief technology officer at the Calgary, Canada-based company. Imaging Dynamics’ Xplorer 1000 retrofit system costs only about $100,000. Its turnkey Xplorer 1700 sells for about $200,000, one-third to half the cost of competing systems.

Like silicon-based plates, CCDs record light flashes produced by a scintillator. Rather than a single chip, however, CCD-based detectors use many individual chips that are electronically linked.

A premier developer of CCD-based systems, SwissRay International, uses fiber optics tied into CCD chips to record light activity on the scintillator. Sales of its products are booming, according to company executives. SwissRay reported booking 30 orders for its direct digital radiography systems in the first quarter of fiscal 2001, end Sept. 30. This compares to just one order in Q1 2000. These orders, coupled with expectations for the next three quarters, should enable the company to achieve profitability during its current fiscal year, which ends June 30, 2002, company officials said.

Medical sales could rise for many vendors in the years to come as costs for making digital technologies fall. By 2003, end users could see CR systems drop in price to $75,000, according to Fuji Medical Systems. In the same time frame, flat panels could drop to $225,000, Fuji predicts. Imaging Dynamics’ Winsor believes CCD-based systems will also drop in price, thanks in part to widening adoption of the technology as a component in consumer digital cameras.

“These cameras don’t have the same type of technology that’s in a high-end scientific system, but (medical-grade) CCDs will get a huge boost because they’re cousins to these other chips,” he said. “Wafer sizes are going to increase, yields will improve, and costs will come down. There’s no similar wave driving the cost of flat panels down.”

A competing technology similar to CCD is complementary metal-oxide semiconductor (CMOS). Each CMOS chip carries an array of cells that receive light and convert it to an electrical charge. Each sensor element and its circuitry deliver a single pixel. Cares Built has been using CMOS technology since 1997, when it introduced its Clarity 7000 digital x-ray detector as a work-in-progress at the RSNA show.

CMOS is relatively inexpensive. Cost, however, is not the only-or even the principal-factor that must be considered when deciding whether to adopt a technology for medical applications. Winsor believes CMOS cannot yet deliver scientific- or medical-grade results. The executives at Cares Built disagree, and Winsor acknowledges that Imaging Dynamics’ scientific advisory board is keeping tabs on CMOS developments.

Identifying newer and cheaper detector technologies, as well as devising ways to make existing devices less costly and more effective, presents a challenge for manufacturers. But that’s just the sort of activity that has to happen before digital radiography can shift from a boutique offering to a market commodity. That day may not be far away.

“It’s more of a commodity market than it used to be,” said Gary Reed, president of Integration Resources, a consulting firm specializing in PACS and RIS in Lebanon, NJ. “But cost is still clearly a big issue.”