USC researchers work with Polaris Dawn to study a new approach to X-ray imaging in space

Today’s space flights typically last from a few days to a few months, so medical treatment on board is mostly limited to first aid. But researchers are increasingly exploring new ground – known as in-flight space medicine – that will be key to maintaining astronauts’ health on longer missions, such as the 21-month round trip to Mars. .

Polaris Dawn, the first of three missions in the Polaris program, pursues an array of new frontiers in space. Scheduled for launch no earlier than March 1, 2023, its crew will aim to reach the highest Earth orbit ever and attempt the first-ever commercial spacewalk. They will also spend up to five days conducting more than 38 human health studies in space, including an effort led by USC’s Keck School of Medicine to study a new approach to X-ray imaging. on board.

Modern x-ray equipment is impractical to send into space due to its large mass and power requirements. But to do real clinical medicine in space on a mission, space medicine in flight, we’re going to need radiology.”

John Choi, MD, PhD, Resident Physician in Interventional Radiology, USC Keck School of Medicine and Project Leader

Ultrasound is the primary diagnostic imaging method currently used in space because ultrasound equipment is relatively portable and does not require a lot of power. But it cannot identify certain life-threatening medical conditions, such as a blood clot in a major artery in the heart, lungs or brain.

For this reason, Choi and his colleagues believe that X-ray imaging and radiology; in addition to other medical abilities and specialties such as surgery, anesthesia and emergency medicine; are essential to effectively respond to medical emergencies in space. They are now exploring an innovative method that could allow clinicians to use ambient radiation in space (always present natural radiation) to collect X-ray images with minimal equipment.

“In space, we know there is more ionizing radiation than on Earth,” Choi said. “Can we take advantage of this radiation as a source allowing us to capture an image?

Harnessing Radiation in Space

To answer this question, Choi and his team leverage the technology of a form of x-ray equipment simpler than modern digital detectors: film. Due to its reduced mass and power, using this simpler equipment to absorb radiation for image generation could eliminate the practical problems of sending equipment into space.

In analog x-ray film imaging, a special “intensifying screen” converts the radiation into visible light, which can then be developed on the film. Researchers send a piece of this intensifying screen into space to test if there is enough ambient radiation to make the screen glow.

Choi and his team assemble the materials needed to conduct the experiment, and the researchers write instructions for the Polaris Dawn crew to use when conducting the experiment on board.

Improving Health on Earth

The experiment, known as a “proof of principle”, is just the first step in establishing whether ambient radiation in space is sufficient to generate X-ray images. If successful, researchers will need to then prove that they can perform clinically meaningful x-ray examinations using the new method.

A technological breakthrough could also offer useful information for X-rays on Earth, as a way to collect images with less radiation. In addition to its goal of advancing human health in space, the Polaris Dawn mission seeks to gain scientific knowledge that could improve medical care closer to home.

“The Polaris Dawn mission profile provides us with great opportunities to expand our collective knowledge of the human body in space and the associated applicability here on Earth,” said Polaris Dawn Mission Commander Jared Isaacman. “Our science and research program will improve the body of knowledge for future long-duration spaceflights that will bring us back to the Moon and Mars, as well as advance our knowledge and understanding of humanity here on Earth.”