Deep space medical imaging goes where no WAN has gone before

Long-term, long-distance medical care of astronauts is becoming an important consideration as NASA anticipates a return to the moon in a few years. A mission to Mars with humans aboard may follow.

Researchers looking for smaller, lightweight imaging options are eyeing ultrasound and the more exotic hyperspectral imaging (HSI) as alternatives to x-ray.

For a six-member crew on a Mars mission lasting 30 months or more, the medical incidence rate is estimated to be 0.90, or about one person per mission. This type of illness would likely require terrestrial consultation support.

Imaging capability is thus a necessity. But digital imaging in its present form may be a "no go" for the next generation of live missions to the moon and beyond.

"Because of mass (weight and footprint) issues, x-ray has not been seen as a viable diagnostic imaging option for medical care in space," said Dr. Ronald Merrell, director of the Medical Informatics and Technology Applications Consortium at Virginia Commonwealth University and chair of NASA's Aerospace Medicine and Occupational Health Advisory Committee.

Instead, imaging attention is focusing on ultrasound, since the concept of telesonography has already been proven in terrestrial consultations, Merrell said.

"There is considerable interest in using ultrasound energy for diagnostic purposes appropriately assigned to x-ray technology on Earth," he said.

Merrell said NASA is also interested in autonomous medical systems based on artificial intelligence and decision trees, as well as computer-aided detection and diagnosis.

"The idea is to develop software support for interpretation of images onboard the spacecraft without real-time reliance on transmission or the demands for great bandwidth to store and forward images," he said.

HSI, a technology that has already found uses in astronomy, chemistry, and agriculture, has also grabbed NASA's attention. This powerful noninvasive technique is capable of providing information about the structure and composition of biological and nonorganic materials in various contexts. NASA may depend on it to detect tumors in astronauts.

HSI involves subdividing infrared, visible, and ultraviolet spectra emitted from objects. Different objects will have different spectral patterns. The technique, which can now detect camouflage and thermal emissions, may be used to detect cervical and breast cancers by capturing the unique color fingerprint of different cells.

The technique's clinical potential includes not only cancer detection, but dermatological applications and retinal imaging to detect pathologies such as diabetic retinopathy, glaucoma, and macular degeneration, according to Richard Gomez, Ph.D., director of the hyperspectral imaging center at George Mason University.

"The potential applications of HSI to medical imaging and the life sciences are enormous," Gomez said.