Upgrades predominate at RSNA show as bone densitometry industry digs in

Most companies aim products at cost-effectiveness

After several years of flat sales, competition in the bone densitometry market is settling into a kind of trench warfare. The major bone-mass measurement companies are digging in with R&D programs aimed at shoring up their product lines rather than gaining new technological ground. This approach was reflected at last month’s RSNA meeting, with most of the new product introductions evolutionary rather than revolutionary in nature.

Cost sensitivity was a major theme. Lunar launched an axial scanner designed to fill a gap in the company’s product line, while Norland unveiled a new spine-femur system. Meanwhile, Image Analysis showcased a desktop peripheral x-ray system similar in concept to a product introduced last year by Schick Technologies, which chose not to exhibit at the 1998 meeting. Hologic focused on new software options for its existing QDR line of densitometers.

Lunar’s new system, called Prodigy, is designed to be a low-cost answer to fan-beam x-ray units being marketed by competitors, in particular those sold by the company’s arch-rival Hologic. With a street price of $60,000, Prodigy is intended as the solution for physicians with tight budgets who want the speed advantages inherent in fan-beam scanners. The new product from the Madison, WI, company is not a conventional fan-beam system, however. Lunar product manager Jim Homuth describes the system as part of a new generation of technology.

“We have done our best to take the best attributes of each class—to look at the advantages offered by pencil beam and by fan beam—and combine them,” Homuth said. “We manipulate the beam into a fan, but we do this in a way that minimizes the disadvantages of conventional fan-beam technology.”

Prodigy uses a narrow beam of radiation similar to a pencil beam, but it structures that beam to fan out longitudinally. The beam moves across the patient in line with a detector made from cadmium zinc telluride (CZT). The beam and the detector traverse the patient until the exam is completed.

A scan of the spine or femur is done in about 30 seconds. A whole-body exam is complete in about four minutes. Overall exam time is less than six minutes, a speed comparable to what can be accomplished with conventional fan-beam detectors. Yet, Prodigy scans are done with 10 to 20 times less dose, according to Lunar.

The system’s speed and low dose are possible partly from the use of CZT, which is among the most efficient materials for detecting x-rays. Lunar has also leveraged a software-driven technique that scans both the right and left femurs automatically. Scanning both bones is recommended as a way to more precisely measure bone density. The disadvantage is the extra time necessary when done manually.

“By centering the scanner on one femur, the machine completes the scan (of this bone) and automatically finds the other,” Homuth said.

Lunar offers a fan-beam system, DPX Expert, but with a street price of $87,000, its cost is too high for the mainstream market, company executives said. Prodigy is being positioned as a mid-tier product between Expert and the company’s value-priced axial scanner, DPX IQ.

Hologic of Waltham, MA, offered no new products, focusing instead on software options and DICOM compatibility for its existing QDR systems. As a value-added service, the company pointed to an osteoporosis learning series.

“It’s meant to teach physicians who are new to bone densitometry pretty much everything they need to know about it,” said Dave Davis, Hologic vice president. “We need services, in addition to our products, to make it easier to acquire and effectively operate equipment, so we can broaden access to osteoporosis exams.”

Norland’s Excel. Norland hopes its new Excel densitometer will expand the company’s lagging fortunes. Financial problems that caused a company-wide reorganization last year tainted Norland’s reputation, but executives at the Fort Atkinson, WI, company hope its broad range of offerings—particularly the new Excel—will bring in customers.

Excel relies on pencil-beam technology, which makes for slower scans than many competing systems. But executives believe that its slow speed will be offset by the advantages of the system: high precision, a small footprint compared with table-based scanners, and an extraordinarily low cost, around $30,000. That’s about what customers would pay for some peripheral dual-energy x-ray absorptiometry (DEXA) units.

Excel cannot do lateral spine scans but can accomplish scans of both the hip and AP (anteroposterior) spine. The limitation is minimal, according to Kym Secrist, Norland marketing manager.

“These two (AP spine and hip) are the most scanned sites and represent sites with the greatest fracture potential, with the exception of the wrist,” Secrist said.

Image Analysis of Columbia, KY, is known best for its quantitative CT (QCT) software, but the company chose the RSNA meeting to unveil a new densitometer. Image Analysis followed the trend in the development of low-cost systems by unveiling a table-top unit that scans the index finger to determine bone density. Unlike other x-ray-based densitometers, Index relies on radiation at four rather than two energies, as in the case of DEXA units.

“It’s a simple device,” said Dipu Ghosh, vice president of engineering for Image Analysis. “You put your finger in, press a button, and you get the bone density.”

The system, which weighs about 20 pounds and plugs into a standard wall outlet, uses a bone/tissue equivalent phantom to self-calibrate before each exam. A built-in LED screen displays results three seconds after the operator pushes the button that fires the x-rays. The company has not yet set a price for Index, which is pending Food and Drug Administration clearance, but Image Analysis executives expect it to cost around $10,000.

In keeping with its past offerings involving CT, IRIS (Institute for Radiological Image Sciences) of Frederick, MD, improved its phantomless QCT system with software enhancements offering trend analysis and DICOM compatibility. Another CT-based company, MindWays Software of San Francisco, improved its 3D QCT product with the addition of the CT XA module. The module turns a CT scanner into the functional equivalent of a DEXA machine by taking a 3-D volumetric data set and degrading it back into two dimensions, according to MindWays’ president Audie Chason.

“We end up with a projection image, which is the technology that DEXA uses,” Chason said.

Establishing equivalence to DEXA opens the door for 510(k) review, a strategic decision by MindWays that is designed to decrease the time needed for the FDA to clear the product for marketing. The company is collecting data to support its FDA submission.

Diagnostic Medical Systems (DMS) of Perols, France, added software to its ultrasound system, UBIS 5000. The unit was unveiled at the 1997 RSNA meeting and has not yet received premarket approval for distribution in the U.S. Enhancements to the system include improved image quality, a unique attribute among ultrasound densitometers.

“With no image, it is like driving with your eyes blind,” said Antoine Rabaste, president director general of DMS.

UBIS 5000 images of the heel, which are produced by mapping the density values of different points in the bone, are colorized to indicate specific thresholds for bone density. Colorization allows more accurate positioning of the region of interest for the first visit, and for follow-ups.

“We believe that (lack of accuracy) is the reason ultrasonometry has not yet been taken seriously. If you compare the same patient on UBIS and another system, you will find very different diagnostic results. With UBIS, you are sure that you are targeting relevant sites,” Rabaste said.