Health and Medicine

Sunday, November 01 2009

Originating Technology/NASA Contribution

In spring 2008, Dr. Scott Dulchavsky diagnosed high-altitude pulmonary edema in a climber over 20,000 feet up the slope of Mount Everest. Dulchavsky made the diagnosis from his office in Detroit, half a world away. The story behind this long-distance medical achievement begins with a seemingly unrelated fact: There is no X-ray machine on the International Space Station (ISS).

On the ISS, diagnosing an injury or other medical issue can be problematic; bulky medical imaging devices like X-ray, CAT, or MRI machines are too large and heavy for costly transportation into space. And while crew medical officers receive some diagnostic training, the nearest doctors and fully equipped hospitals are 250 miles away on Earth. Future astronauts on long-term Moon or Mars expeditions will face even greater challenges.

The ISS does have an ultrasound machine—at 168 pounds, much smaller than its imaging technology counterparts—installed as part of the Human Research Facility for experiments on the effects of microgravity on human health. During medical use, the ultrasound machine’s hand-held transducer emits high-frequency sound waves that partially reflect at points of differing density, such as between soft tissue and bone. The machine’s computer translates the echoes into a two- or three-dimensional video representation. On Earth, ultrasound is commonly used for imaging fetus development, abdominal conditions like gallstones, and blood flow in patients with arterial disease. Unconventional applications, like diagnosing broken bones or collapsed lungs, were not explored given the ready availability of X-ray and MRI machines in hospitals and the high density differences of bone and air, which completely reflect the ultrasound waves and prevent clear images of deeper tissue.

That changed in 2000, when NASA approached Dulchavsky, chair of the Department of Surgery at Henry Ford Hospital in Detroit, to make ultrasound a more versatile diagnostic technique and to adapt it for remote use on the ISS. Dulchavsky tested new ultrasound applications and found that, in many cases, such as with collapsed lungs, the technique worked better than X-ray imaging. He became lead investigator for the Advanced Diagnostic Ultrasound in Microgravity (ADUM) experiment, a collaborative effort between Johnson Space Center, Henry Ford Hospital, and Wyle Laboratories Inc. in Houston.

Aided by Onboard Proficiency Enhancer (OPE) software, cue cards, and direct communication with doctors on Earth, ISS crewmembers with only minimal ultrasound training (about 3 hours as opposed to about 500 hours for a professional) used non-traditional ultrasound techniques pioneered by Dulchavsky’s team for imaging of a wide range of body parts. These novel ultrasound techniques can evaluate infections in the teeth or sinus cavities or judge the effects of space flight on the central nervous system by measuring changes in the diameter of the eye’s optic nerve sheath as a gauge of pressure around the brain. Experts on the ground received diagnostic-quality images from the ISS through satellite downlink, demonstrating the effectiveness of ultrasound as a multipurpose, remote diagnostic tool in space.

Partnership

In keeping with NASA’s mandate to translate space technologies into applications for terrestrial use, Henry Ford Hospital doctors and Wyle engineers worked to find ways to overcome a major obstacle to bringing the ADUM-developed remote ultrasound procedures down to Earth: There were no cost-effective, technologically viable methods for sending ultrasound scans over long distances without a loss of image quality.