Philips unveils flat-panel cardiac cath system at ACC

Digital detector offers dose and space benefits

Long before Royal Philips began buying up ultrasound, nuclear medicine, and multimodality vendors, Philips Medical Systems was a contender in the medical imaging industry, largely due to its strong offerings in cardiovascular imaging. The Integris Allura 9, a cardiac cath system equipped with a flat-panel detector, is designed to add to that core capability.

The new system, which was formally unveiled March 17 at the annual meeting of the American College of Cardiology in Atlanta, allows customers to swap the traditional 9-inch image intensifier (II) for a digital detector based on amorphous silicon. The panel captures 30 frames per second and delivers spatial resolution of 180 microns. Customers who choose the flat-panel option will pay a premium, said Bert van Meurs, Philips' marketing director for cardiovascular systems in Best, the Netherlands. He refused to say exactly how much.

"We have optimized and further innovated the Integris Allura family," van Meurs said. "We have proven the (digital) technology and have put it into a proven design."

The new Allura 9 will not be the first commercial release of a cardiac cath lab equipped with a digital flat-panel detector. GE's Innova 2000 earned that honor some two years ago (SCAN, 3/15/00). Philips' decision to equip its product with the this type of detector illustrates the evolution of the technology, however, and will likely accelerate its acceptance.

Philips is widely acknowledged as the world leader in cardiovascular imaging. Philips analysts

estimate that the company has more than 40% global market share. Its nearest competitors, GE and Siemens, are in the mid-20%s, according to these analysts.

The company's position as a market leader dictated a cautious approach in the development of flat-panel technology, van Meurs said. Detector technologies have been studied and evaluated secretly by Philips for the past three years.

Early flat-panel technology achieved a resolution of 200 microns per pixel, which Philips concluded was not good enough. Spatial resolution was eventually improved to 180 microns. Temporal resolution was improved by developing a "reset light" that blanks the photodiode array after each exposure, thereby eliminating residual or ghost images. Dose efficiency was improved by increasing the width of the cesium iodide layer that serves as a scintillator, turning x-ray strikes into flashes of light to be read by the underlying array of photodiodes.

Trixell, which is producing the detector now being integrated into the Allura, also provides the Pixium 4600 digital detector that is built into Siemens and Philips radiographic equipment. Trixell's latest development, the Pixium 4800, was shown for the first time at the annual meeting of the European Congress of Radiology (see related story, page 4).

The new Allura 9, which can be configured as a ceiling-suspended or floor-mounted system, supports the same clinical applications as the current configuration featuring a 9-inch II, van Meurs said. The "G" arm bearing the flat panel can rotate just as quickly as when an II is attached, he said, arcing up to 240° in about four seconds. (Rotational angiography on the 9-inch cardiac system will be largely confined to carotids, van Meurs said, although research into volumetric reconstructions of coronary vessels is under way.)

The flat panel can be integrated into a single- or biplane system. Different configurations may include a 9-inch flat panel or a combination with IIs up to 15 inches across to support peripheral angiography.

Image quality remains unchanged from what can be achieved with the 9-inch charge-coupled device-based II, and the flat panel allows better dose efficiency, van Meurs said. Working with the rest of the imaging chain, the new digital technology can cut dose by up to 50%. The compact nature of the flat panel also provides improved access to the patient.

Philips executives noted the flat panels have begun arriving at the Philips assembly line in Best. A steady stream of one to three is expected each month from now on.

On the floor of this facility, DI SCAN spotted an Allura 9 equipped with a flat panel being prepped for shipment to a site in Brazil. The customer is a luminary for Philips cardiovascular products, van Meurs said, noting that the first commercial shipments of the new system are not scheduled until April. Commercial production is only beginning to ramp up, and it will be a slow process.

"We are doing a controlled release of the product in order to guarantee reliability and quality," van Meurs said. "We have to maintain the high standard on which our reputation is built."

If Philips receives more orders for cardiac flat panels than it can meet, customers will have the option of waiting or buying an II-based system that can be upgraded when a flat-panel detector becomes available, van Meurs said.

In mid-March, Allura 9s with flat panels were operating at about a half-dozen sites in various countries. Luminaries at these sites have allowed Philips to achieve a leadership position in cardiovascular imaging, according to van Meurs, helping to work out the bugs in new equipment while providing clinical experience that others in the community can follow. They are helping Philips optimize parameters and image processing techniques on the new system, using its dynamic range to further improve image quality, he said.

These opinion leaders could further benefit the company as the medical community continues to evolve. Minimally invasive interventions are becoming more popular, van Meurs said, attracting surgeons as well as an increasing number of radiologists and cardiologists. The more physicians perform these procedures, the greater will be the demand for interventional imaging equipment. This demand extends beyond the Allura 9, which is dedicated to cardiac, but the Integris Allura line supports vascular and neurological interventions as well.

Development of the Allura 9 underscores Philips' engineering capability and could promote the company's cardiovascular x-ray line in general.