French Device Acquires Lateral, Frontal Radiographs Simultaneously

Technology that 15 years ago led to a Nobel Prize in physics is today the cornerstone of a unique DR system that promises up to a 90% cut in radiation dose for body skeletal images compared with film systems. It produces both front and lateral views from head to toe in as little as 20 seconds.

The key is a particle detector invented by Nobel laureate Georges Charpak, adapted for medical radiography and built into the EOS low-dose 2D/3D orthopedic scanner by the French firm biospace med. Two slot-scanning digital detectors paired with x-ray tubes and mounted orthogonally on a vertical C-arm sweep the length of the patient in one continuous motion. Data can be displayed separately as lengthwise images, free from the distortion that can occur when conventional DR systems stitch together static images to cover a patient. Or, the frontal and lateral swipes of the body can be combined into a volumetric image.

The EOS scanner can be set to sweep the entire length of the body or just part of it. In either case, the digital radiography device visualizes the bones and joints of the standing patient in a weight-bearing posture. This exposes balance and posture issues that can be valuable when planning surgery, she said. The system also automatically measures bone length and joint angles, quantifying these otherwise subjective analyses.

The combination of a continuous scan and Charpak's ultrasensitive detector cuts dose by 50% to 90% compared with film images, depending on the patient, according to Marie Meynadier, president and CEO of biospace med.

"When we compare our doses with what you might get during a CT scan, we cut patient radiation exposure by a factor of 100 to 1000," she said.

EOS' ability to image the lower limbs and spine could prove especially important for the more than 900,000 scoliosis patients in the U.S. who must undergo periodic radiographic exams to monitor disease progression and gauge the effectiveness of treatment. Most of these patients are children who, because of the need for repeated exams, benefit from a device that minimizes radiation exposure.

At around 325,000 euros, the device is priced higher than competing devices-and that's only for the 2D configuration. Adding 3D will bump the price up a bit, although not a lot more, Meynadier said. She contends that the improvements in quality and the increased throughput possible with the device more than compensate for the higher price.

"At one of our investigational sites, we can put through about 50 spine patients in a morning," she said.

-By Greg Freiherr