Press Release

NASA Image Fusion Will Help Doctors Examine Astronauts’ Hearts in Space

By SpaceRef Editor
April 3, 2007
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NASA Image Fusion Will Help Doctors Examine Astronauts’ Hearts in Space
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Practicing medicine on trips to the moon will be harder than on Earth, because spaceships will be far away, and few doctors will be aboard.

NASA scientists are studying ways to improve space medicine to tackle space travel’s medical challenges. One effort is to develop ‘image fusion.’ In this process, clear, sharp x-rays and other high-resolution, scanned images of astronauts taken on Earth will be combined with less sharp sonograms taken onboard spacecraft to enhance those images. These improved images will enable doctors to better see the condition of major organs in astronauts.

Sonogram scanners use non-invasive sound waves to take pictures of organs and features inside the body. Doctors also use sonograms to view and monitor unborn babies. Because sonogram scanners often are lighter and use less power than other kinds of scanners, they are better suited for space travel.

“We want to be able detect any changes (in astronaut) organ structure and function during spaceflight,” said Richard Boyle, a scientist and neurology expert at NASA Ames Research Center in California’s Silicon Valley. Neurologists study the nervous system and potential neurological medical problems.

“This would allow us to provide early intervention to resolve medical (problems) before they become more serious. There will be very limited diagnostic tools available to the astronauts, and this image fusion may provide a way to help astronauts maintain their health,” Boyle said.

Small space crews probably will include only one or two medical doctors. Though potentially thousands of doctors and other specialists on Earth also will be on call to help crewmembers during spaceflight, home-planet medical specialists and their massive equipment will be far from spaceships or astronauts walking on the moon.

“In order to investigate any potential changes that may occur during long-term space travel, we have selected the human heart and kidneys as our initial study subjects,” Boyle observed.

According to Xander Twombly, a colleague of Boyle’s, “We’re working on development of a digital model of the human heart and kidneys. This is a computer model of the heart that can be used to predict changes in heart function under different gravitational conditions,” Twombly explained.

“We’ll be using computerized tomography, commonly known as CT scans — which are 3-D x-rays – to take pictures of the beating heart on Earth prior to spaceflight,” explained Twombly. “These x-rays provide much higher-resolution pictures of the heart than an ultrasound scanner can provide. We’ll take ultrasounds (of the heart) on the Earth as well, before spaceflight, and then we’ll combine the ultrasound and the CT images to make an enhanced picture of the heart,” Twombly explained.

According to researchers, they are using the power of computers to tie x-ray details to lower-resolution ultrasound scans, so that when ultrasounds are taken during space travel, they will be sharper and show more detail.

“We’re also practicing nuclear medicine to view muscles at work in the heart,” said Boyle. Scientists use nuclear medicine to view processes in living organisms by injecting radioactive substances that muscles use during movement. The radioactivity is detected by charged coupled device (CCD) sensors to produce 3-D images. Consumer digital cameras also use CCDs to capture images.

NASA has teamed up with doctors to develop image fusion for sonograms. Collaborations also aid in the spin-off of new technologies, like image fusion.

“Our collaboration is with Salinas Valley Memorial Healthcare System (SVMHS), down the road from us in Salinas, Calif.,” Boyle noted. “We have a Space Act Agreement with them. They provide all the imaging and medical expertise, and NASA provides the computer science know-how and systems to develop image fusion technology. Our group has had close interactions with SVMHS Sam Downing, President/CEO, the doctors and staff at Salinas for at least eight years to develop a wide variety of medical imaging technologies,” Boyle added. Dr. Richard Villalobos is the principal investigator at Salinas Valley Memorial Hospital working with Boyle and Twombly.

Talking about spin-offs, Boyle said, “This could also be used for remote medical diagnostic imaging. This means scientists working in an Antarctic station could provide continuous ultrasound images of their vital organs to medical doctors to monitor future medical problems,” he continued.

“In Third World telemedicine, you can bring a patient to a clinic, and a technician can use ultrasound to record a patient’s organ, and how it changes over time,” Boyle explained. Doctors at a distant hospital could then evaluate these enhanced ultrasound images remotely to track patient progress, according to Boyle.

“The key thing here is that right now, doctors can use ultrasound and telemedicine to evaluate patients, but the ability to enhance the ultrasound image with the previously recorded CT scan of the patient is not available, and that’s the whole purpose of our development work,” Twombly explained.

“A lot of our research is to validate if this technique can accurately represent organs’ conditions with these CT-like images,” Twombly observed. During the validation process, scientists use ultrasound to take images of human organs during centrifuge rides, and during microgravity flights on airplanes that fly big loops to create short periods of weightlessness – and various gravity conditions.

“This will test our ability to predict what happens to organs during different gravity conditions from microgravity to several gravities (Gs),” Boyle said. “If we were to pursue the telemedicine question . . . following a person with ultrasound after only a single CT scan at the outset, then we would need to take CT scans on a medical schedule and compare our ability to predict future CT scans (using just ultrasound). But we have no plan at this time to do that,” Boyle said.

Scientists also want to learn how the space environment affects the human body during spaceflight, and when astronauts are exploring the moon. “The imaging data then would be combined with a computerized model of the human body,” Boyle said. The two scientists say these models commonly show blood flow within the heart, muscle movements and kidney function. The new data from the enhanced ultrasound will add more detail to these models.

According to Boyle, if the image fusion techniques were validated with ground-based studies, the next step would be to conduct tests in space. Subjects would be scanned with many kinds of imaging technologies, such as magnetic resonance imaging (MRI), positron emission tomography (PET) and single photon-emission computer tomography (SPECT) to construct a ‘multi-dimensional model’ of individuals before space missions. During flight, new ultrasound images would be taken, transmitted back to Earth and merged with the subjects’ computerized models. Researchers would fuse these images with ultrasound images of each astronaut’s organs.

“One of the things (we would like to do is) to have some images taken during the launch when the astronauts are subjected to high-g loads, to see whether or not we can capture any short-duration effects on the human body. Another phase of interest is when the human body travels from several gravities to a state of near-weightlessness in orbit,” Boyle added. During these flights, the human body needs to adapt to the new, microgravity space environment, according to the scientists.

“This research, that will combine the information obtained from initial CT images with follow-up ultrasound images in an individual, holds great promise for protecting the health of astronauts on exploration missions to other planets. More importantly, this may be a big help to patients and doctors here on Earth for following medical conditions, since the patient would receive lower radiation doses, the ultrasound would be easier to get for the patient, and may cost less,” said Dr. Victor Schneider, senior medical advisor in the Office of the Chief Health and Medical Officer, NASA Headquarters, Washington.

For images related to this story, please visit:

http://www.nasa.gov/centers/ames/multimedia/images/2007/imagefusion.html

SpaceRef staff editor.