Synchrotron breathes life into research
Issue 18 | November 2006
Report: Penny Fannin
Photography: Greg Ford
|Breathing easy: Researchers Dr Megan Wallace, Dr Stuart Hooper and Dr Marcus Kitchen hope synchrotron images of lungs will help improve the treatment of premature babies.
Premature babies often have breathing difficulties. At birth, their immature lungs are filled with liquid when what they need is air. Now, with the use of synchrotrons, Monash researchers are investigating ways of helping babies breathe easier.
At 24 weeks, a human fetus is developing taste buds and has defined lips and eyelids and the ability to kick. It also has lungs filled with liquid, which poses a challenge for doctors who deliver premature babies.
Faced with a very premature baby, a big question for doctors is how much oxygen to deliver to their immature lungs. It's an inexact science. The amount of oxygen required varies from baby to baby, and the time taken for the lungs to fill with air is also variable.
But a team of Monash researchers is seeking to make the science of lung aeration more exact by examining the lungs of immature mammals with the aid of a synchrotron.
Synchrotrons are machines about the size of a football field that accelerate electrons to close to the speed of light. Intense light in a range of wavelengths is produced when the fast-moving electrons are forced by magnetic fields to change direction. This light can be used to study the structure of objects down to the atomic level.
The Australian Synchrotron is being built at Monash University and will be opened in 2007.
But that hasn't stopped the lung research from being done. Professor Rob Lewis and Dr Marcus Kitchen from the Monash Centre for Synchrotron Science and Dr Stuart Hooper and Dr Megan Wallace from the Department of Physiology have recently returned from the SPring-8 synchrotron in Japan , where they were studying the lung function of newborn rabbits.
In the first experiment of its kind using live animals, they were studying how fluid is cleared from the lungs after birth by taking X-ray images of the rabbits' lungs immediately after they were delivered by caesarean section.
Dr Kitchen said the process, which does not harm the rabbits, produces much higher resolution pictures than conventional X-rays. 'We use the images to calculate how much air goes into the different regions of the lung and how long it takes to get there," he says.
The research could eventually lead to better ways to treat the thousands of premature babies born each year in Australia who may have to be artificially ventilated because their lungs are not fully developed.
The lungs of the fetus are filled with a liquid that helps the lungs to develop properly. The liquid is normally cleared during labour. However, premature babies are not very good at clearing the liquid from their lungs, Dr Wallace says.
"If the lungs are still filled with liquid, it is difficult to get air into them; this is a huge problem for neonatologists dealing with premature babies," she says. "We also don't know how ventilating the lungs affects the clearance of liquid from the lungs and therefore how well they aerate."
The research at SPring-8 is seeking to understand where the air goes when there is still liquid in the lungs and how long it takes for the lungs to fill with air.
"With the images from the synchrotron, we can actually see what parts of the lungs are filling with air, how long it takes and where the air goes," Dr Wallace says. "By doing that, we can look at the effect of ventilation and determine if there are better ways for doctors to ventilate the lungs that will improve the outcome for the baby."
Already, says Dr Wallace, the studies have produced valuable results. They have shown that it can take more than two hours for the lungs -- which they aerate in stages -- to fully fill with air, and that body position is important.
"There's a huge amount of variability in the time it takes to aerate the lungs, and we've found that body position has a really dramatic effect," she says. "If the rabbit pup is lying on its side, the side that is uppermost fills completely with air but the other one fills much more slowly. Yet when the pup is upright, the midsection of the lungs fills first.
"Now that we have this basic information, we can look at testing some of the interventions that clinicians use and identify the best strategies for aerating the lungs."
Dr Kitchen says the images produced by the synchrotron are particularly useful as they reveal the gas-exchanging regions of the lungs, right down to the smallest gas-exchanging units.
"This is important to see because that's where the function of gas exchange is occurring," he says. "We can use the images to determine the stage of lung development and to see if the air is actually making it to the gas-exchanging areas, because if it's not making it there gas exchange can't occur."
What's more, the beauty of using a synchrotron to gather this information is not only the quality of the images, Dr Kitchen says. The techniques used also do not require prolonged exposure to high levels of radiation or the inhalation of 'contrast media' that allow the lung structures to be clearly displayed.
"If we were to use magnetic resonance imaging, we would need to have the rabbit pups inhale a contrast agent, but in this case the air itself is the contrast medium so the rabbits are just naturally breathing, and the radiation dose is low so we can take live images over a prolonged period of time."