Siemens prepares to launch 64-slice, wide-gantry CTs

FDA clears the way for initial sales

Siemens Medical Solutions took a giant step closer to market with its two new CT systems, the Sensation 64 and the Sensation Open, after they cleared the FDA earlier this month.

Sensation 64, named for the number of submillimeter slices produced per 0.37-second rotation, is one of four megaslice scanners being prepared by major CT vendors as successors to the 16-slice flagships now on the market.

An extrawide gantry and an extended field-of-view distinguish Siemens' new Sensation Open. The company is positioning the system as the only wide-bore gantry CT scanner offering 16 slices per rotation. A primary application will be in oncology. Others will address trauma and interventional procedures. The Open is especially suited to scanning obese patients.

Sensation 64, which will list for $1.5 million, will accommodate standard radiological applications, but its speed of rotation, extended coverage, and increased resolution make it a natural for cardiac scanning. It was first unveiled at the 2003 RSNA meeting,

Its first clinical site will begin operating later this month, and several others will start up in the coming months. Routine deliveries are expected to begin in November.

Sensation 64 is unique in its design, delivering 64 slices with just 32 rows of detectors. A specially designed x-ray tube, called the Straton, utilizes two focal points in the anode to generate two overlapping x-ray beams. This overlap is achieved by precisely deflecting the electron beam within the x-ray tube. Each row of the detector produces a double readout to boost spatial resolution.

"We have discovered, after talking to our medical advisors, that what people are looking for is not a new scanner that can go faster and faster but a scanner that can be as fast as necessary and delivers better resolution in the z direction," said Murat Gungor, Siemens' U.S. marketing manager for the Sensation family.

Sensation 64 does exactly that, he said. The system can achieve 0.4-mm resolution, compared with 0.6 mm with the Sensation 16, with no increase in dose. Yet it covers the heart in about eight seconds. Cardiac imaging will be a major application, but Siemens plans to position the system for general radiologic applications, particularly neurology, pediatrics, and trauma.

Sensation 64 includes Siemens' proprietary WorkStream4D for workflow optimization and data handling; syngo InSpace4D, an advanced 3D medical imaging application for evaluating the heart; and CARE Dose4D for automated real-time dose adaptation.

The Sensation Open incorporates the Straton tube technology found on the Sensation 64, but not the special Double z-Sampling capability, which doubles the number of slices per detector row. The Open is distinguished not by the number of slices it can produce but by its versatility in accommodating special applications.

Whole-body oncology scans for radiation therapy planning can be done in as little as 25 seconds. Alternatively, the system can be used for lung cancer screening or virtual colonography. The wide-bore gantry is a plus for interventional procedures, as well as for scanning obese patients.

"This is a scanner for everything," Gungor said.

The new wide-bore CT is only now being prepared for installation at clinical sites. The first will begin operating next month in Europe, and the U.S. will get its first Sensation Open in July. Full production is scheduled for November.

Siemens is not the first company to introduce a multidetector CT designed with an extrawide gantry. GE Healthcare showed its LightSpeed RT at the RSNA meeting six months ago. Sensation Open beats the GE product, however, in gantry diameter (82 cm versus 80 cm), extended field-of-view (82 cm versus 65 cm), and slices (16 versus four). Conventional CT simulators typically offer single-slice capability and a 50-cm field-of-view.