Teleradiology launches toward the final frontier

Now that the International Space Station is permanently inhabited and space tourism looms as a possibility, digital radiography to support medical care in space has become a hot topic.

While ultrasound remains the modality of choice for orbital medicine, it will never provide all the answers, said Dr. Rob Hart of medical imaging science at Curtin University of Technology in Perth, Australia.

"The chest x-ray is something ultrasound will never be able to do," Hart said. "Some form of miniaturized DR technology will be required. A combined ultrasound/DR approach will provide all the imaging clinically indicated in most cases in space."

Because ultrasound units are small, flexible, safe, and sturdy, ultrasound is currently the only imaging capability NASA supports in space. ATL's HDI5000 ultrasound system, launched ostensibly for biomedical research, was placed aboard the ISS last year. It provides the only medical imaging for clinical contingencies in orbit.

In the absence of radiographic capabilities in space, Dr. Ashot Sargsyan and colleagues at the Johnson Space Center in Houston are looking at new applications of ultrasound in exotic conditions, such as the diagnosis of pneumothorax (Am Surg 2001;67(3):232-235).

Hart sees this ultrasound trend continuing, at least until smaller, lighter DR devices evolve. Digital radiography in space is limited because launch costs are in the region of $20,000/kg, severely restricting the volume, weight, and power of medical hardware.

In a recent paper (Aviat Space Environ Med 2002;73(6):601-606), Hart proposed a modified, free-floating radiographic C-arm device equipped with a digital detector that would use teleradiology support.

Some modification of the U.S. Army's portable DR system might be useful. Dr. Kenneth Cho of the radiology department at Tripler Army Medical Center in Honolulu has built a portable DR prototype designed to support combat medicine. His first unit, at 250 pounds, would still cost $2 million to launch into space. Lighter and thinner DR sensors have since been manufactured, however.

Beyond portability, Hart believes space applications demand clinically relevant imaging.

"We need instruments that are intuitive and easy to use, so nonspecialist operators can be taught to take pictures that actually assist in patient management," Hart said.

Medical imaging will have to develop into something resembling a plug and play discipline, with highly focused and clinically tested healthcare outcomes.

"We must demonstrate improved patient outcomes for any system that is finally installed. That will require a significant amount of time and resources independent of the hardware development phase," he said.