The Large Hadron Collider at CERN. Credit: CERN/LHC
Electromagnetism is one of the fundamental forces of the universe, responsible for everything from electric and magnetic fields to light. Originally, scientists believed that magnetism and electricity were separate forces. But by the late 19th century, this view changed, as research demonstrated conclusively that positive and negative electrical charges were governed by one force (i.e. magnetism).
Since that time, scientists have sought to test and measure electromagnetic fields, and to recreate them. Towards this end, they created electromagnets, a device that uses electrical current to induce a magnetic field. And since their initial invention as a scientific instrument, electromagnets have gone on to become a regular feature of electronic devices and industrial processes.
A full-sized MRI on the International Space Station would take up a lot of size and mass, meaning the astronauts have to use different machines to learn about the body. Here, Russian cosmonaut Gennady Padalka (left) does an ultrasound on NASA astronaut Mike Fincke during Expedition 9 in 2004. Credit: NASA
OTTAWA, CANADA – The University of Saskatchewan hopes to fly a wrist-sized MRI to the International Space Station by 2016 in a standard Progress cargo flight, according to Gordon Sarty, a university professor specializing in medical imaging. Why is this important? It will help doctors keep track of the astronauts’ bone strength on orbit, Sarty says of his team’s invention.
With NASA aiming to run its first one-year mission to the station in 2015, there is renewed emphasis on keeping track of all the nasty things microgravity does to astronauts’ bodies in space. Crew members spend two hours a day exercising, but still come back to Earth having trouble balancing, with weaker bones and muscles, and possible facing changes to organs such as the eyes.
Although NASA runs MRIs on crew members before and after flights, Sarty said the ability to get even a simple scan in orbit would be useful — and quite quick. It would take just five to 10 minutes to perform, and would be simple for anyone to do as the scan would commence at the touch of a button.
There are many ideas for investigating bone health in astronauts. Here, astronaut Doug Wheelock uses an Acoustic Vibration Bone Quality Measurement Device in 2004 during NEEMO 6, one of an underwater series of missions NASA ran to simulate space exploration. Credit: NASA
The Canadian Space Agency is allowed just 44 kilograms (97 pounds) to get the MRI to orbit under its utilization agreement on station (which is based on funding). A full-size MRI able to fit in a standard payload rack would have been about 800 kilograms (1,765 pounds), Sarty said.
Modifications are necessary. Rather than using superconducting magnets to do the work in orbit, Sarty’s design proposes manipulating radio frequency waves instead. (More technical details here.) Sarty’s team currently has a $240,000 grant from the CSA to develop the technology, which goes for about the next year.
Sarty said the International Space Station needs to be outfitted to a “Level 4” standard of medical care, meaning that it would include medical imaging on board to help monitor crew health. NASA’s Human Research Program Utilization Plan for the station (published in 2012) identifies the addition of ultrasound as a boon to ISS’ medical capabilities.
Russian Soyuz spacecraft, docked to the International Space Station. Although Earth is close by for station missions, NASA’s standard of medical care for station has assumed a return to Earth could take days. Credit: NASA.
As for “Level 4”, the NASA Space Flight Human Human System Standard (latest version available expired in 2012) defines Level 4 as “A moderate to high level of potential risk exists that personnel may experience medical problems on orbit. Risk to the mission is greater for medical issues beyond routine ambulatory medicine.” It also assumes a return to Earth can take days. Level 4 applies to Earth, lunar or planetary missions greater than 30 days, but no more than 210 days.
The upside for Earth research? The portable MRI could be repurposed, in a sense, to bring into more remote regions. This is especially true of Canada, where tens of thousands of people live in scattered communities in the remote north.
Microgravity — or “zero-g” as it’s sometimes called — is not a natural state for the human body to live in for prolonged periods of time. But that is what today’s astronauts are often expected to do, whether while on expedition aboard Space Station or during a future voyage to the Moon or Mars. A host of physical issues can result from the space environment, from bone loss and muscle atrophy to the risks associated from increased exposure to radiation.
Now, there’s another downside to long-term life in orbit: eye and brain damage.
A team of radiologists led by Dr. Larry A. Kramer from The University of Texas Medical School at Houston performed MRIs on 27 astronauts, measuring in each the shape and thickness of the rear of the eyes, optic nerve, optic nerve sheath and pituitary gland.
In 7 of the 27 astronauts flattening of the backs of the eyes was noted, and enlargement of the optic nerve was detected in nearly all of them — 26 out of 27.
In addition, four exhibited deformation of the pituitary gland.
The optic nerve. (NIH)
The changes to the eyes and optic nerves are similar to what are typically seen in those suffering from idiopathic intracranial hypertension (IIH), a disorder characterized by increased pressure within the skull. Symptoms typically include headache, dizziness and nausea, and if left untreated it can produce permanent vision loss through optic nerve damage.
“The MRI findings revealed various combinations of abnormalities following both short- and long-term cumulative exposure to microgravity also seen with idiopathic intracranial hypertension,” said Dr. Kramer. “Microgravity-induced intracranial hypertension represents a hypothetical risk factor and a potential limitation to long-duration space travel.”
Chief of flight medicine at NASA’s Johnson Space Center, Dr. William J. Tarver, noted that although no astronaut has been kept from flight duties as a result of such risks, NASA will continue to “closely monitor the situation” and has placed the potential danger “high on its list of human risks.”
The team’s paper was accepted into the journal Radiology on Feb. 1.
“Orbital and Intracranial Effects of Microgravity: Findings at 3-T MR Imaging.” Collaborating with Dr. Kramer were Ashot Sargsyan, M.D., Khader M. Hasan, Ph.D., James D. Polk, D.O., and Douglas R. Hamilton, M.D., Ph.D.
Update Oct. 24, 2013: Further investigation by researchers at Houston Methodist and Johnson Space Center have shown more evidence of long-term eye damage after just two weeks in orbit. Read more.
