Siemens, Philips, and Thomson join forces to form digital detector developer Trixell

New company debuts at ECR meeting, plans 1998 shipments

Despite x-ray's unenviable status as the least glamorous imagingmodality, the technology still produces some 70% of the data usedin radiology. Because those data must be digitized for radiologyto truly move into the digital era, a host of competitors havegone public over the past two years with their plans for developingdirect x-ray digitization systems.

At this month's European Congress of Radiology meeting in Vienna,yet another rival emerged, one with a distinguished lineage thatmay give it an inside track on its digital x-ray competitors.The new firm, Trixell SAS, is a joint venture between SiemensMedical Engineering Group, Philips Medical Systems, and ThomsonTubes Electroniques, the French developer of image intensifiertubes.

Trixell was incorporated on Feb. 26, after Siemens, Philips, andThomson received an antitrust waiver from the European Union toform the new company. Thomson owns a 51% stake in Trixell, withSiemens and Philips each holding 24.5%. The new firm will be basedin Moirans, France, near Thomson's manufacturing facility in Grenoble.Trixell's work force consists of 45 people, and will grow to 100over the next three years.

Trixell's mission is to develop a flat-panel digital detectorthat can be used in place of image intensifiers and x-ray filmcassettes, according to Gerard Daguise, the Thomson veteran whois president of Trixell. Another Thomson executive, Jean Chabbal,has been appointed Trixell's managing director.

Trixell's technology represents a confluence of work done by itsconstituent companies, all of whom began working independentlyon digital detectors years ago. In 1986, Thomson started investigatingthe basic technology of using active matrix amorphous siliconfor digital imaging. Siemens did similar work in the 1980s, butjoined Thomson in 1991, taking over development of clinical applicationsof the technology. Meanwhile, Philips had been working independentlyon solid-state detectors with other firms, concentrating on digitalfluorographic imaging. When it joined the Siemens and Thomsoneffort in 1995, Philips added its expertise in this area.

Why the decision to join forces? While the firms realized thehuge potential market for digital x-ray technology, they alsorealized that the R&D costs involved could sap much of theproject's return on investment, according to Jan Kees van Soest,director of industrial policy and technology at Philips.

"We (Philips) recognized that the whole effort to productizethis technology would require a considerable amount of time andinvestment, as it would also for Siemens and for Thomson,"van Soest said. "That led us to the decision to proceed withthis engineering and application phase with the three of us."

OEM emphasis. Trixell's flat-panel detector uses a scintillatorlayer of cesium iodide, which converts x-rays into visible light.The layer is coupled to amorphous silicon photodiodes, for conversionof the light into digital data. The data are processed by thepanel's readout electronics and are output as DICOM-compatibledata that can then be sent to a workstation or into a PACS network.The first generation of the detector is for the digitization ofstatic x-ray studies, although future versions of the detectorwill support dynamic studies such as fluoroscopy or angiography,Chabbal said.

The detector has a resolution of 3.5 line pairs per mm, whichis comparable to x-ray film. It has a pixel size of 143 microns,while its quantum efficiency (QE) is 65 QE at 70 kV. When completed,the detectors should have more contrast resolution than film,according to Joachim Alexander, senior director and project managerin Siemens' angiography, radiography/fluoroscopy, and radiographicsystems group. These specifications should also result in lowerx-ray doses for patients.

Trixell hopes to place the first beta versions of its detectorsat clinical sites this year, with completed detectors ready toship to imaging vendors by the middle of 1998. Trixell will supplythe detectors not just to Siemens and Philips but to all medicalimaging OEMs, which will incorporate them into their own x-raysystems. The OEMs will be responsible for final system integrationand for receiving regulatory approval for the finished products.

Despite the common origin of the detectors, Trixell officialsdo not believe that x-ray systems using the devices will be identical.Each company will add its own technology to produce systems thatare unique, according to Daguise.

"This collaboration is at the level of a key component ofan x-ray system," Daguise said. "There is enough roomaround the components for Philips, Siemens, and other OEMs tooffer different types of equipment with different performancelevels."

Trixell's development time line coincides with that of SterlingDiagnostic Imaging of Glasgow, DE, which is developing a flat-paneldetector based on selenium that it intends to commercialize in1998. Another entrant in the digital detector race, Xerox PaloAlto Research Center spin-off dpiX, has begun supplying evaluationkits of its FlashScan 20 sensors to OEMs, which will help vendorsdevelop completed systems.

Besides dpiX and Sterling, Japanese imaging vendor Canon displayeda flat-panel amorphous silicon detector at the ECR meeting (seestory, page 2). Trex Medical of Danbury, CT, and Optical ImagingSystems of Northville, MI, are also developing flat-panel sensors.In addition, x-ray digitization systems based on charge-coupleddevice (CCD) technology are being developed by firms like Swissrayof Hitzkirch, Switzerland; Oldelft of Delft, the Netherlands;Imix of Tampere, Finland; and Konica of Tokyo.