Innovation and Technology News
Tracking frees up PET scanned lab rats
PET rats More accurate PET scans of lab rats may now be possible thanks to a new Australian development that tracks and accounts for the rodents' movements in the scanner.
"The method we're using involves tracking the head motion while the animal is being imaged and then accounting for that motion," says Andre Kyme, who did the research as part of his PhD under the supervision of Associate Professor Roger Fulton.
"That means the animal can have a scan while it's awake and moving."
Among other things positron emission tomography (PET) scanning allows doctors to diagnose cancer. It also helps researchers study the progression of diseases and test treatments.
A patient or experimental animal is injected with radioactive tracer molecules, which then light up in the PET scanner giving a window on what is happening in the body and where.
PET scans of animals are often relied on as the first step in research, but the animals usually need to be anaesthetised so they don't move around.
"Motion basically wrecks the scan," says Kyme. "It will be blurry and it will be very difficult to see any meaningful structures in the image."
PET scans of rat brains are used, for example, to study disorders such as Parkinson's disease.
In this condition researchers use PET scans to study dopamine levels in the brain.
The problem is, anaesthetic can affect dopamine levels and give an inaccurate scan.
"Anaesthesia is widely known to confound the measurements you make in the brain," says Kyme "It can affect the physiology of the animal and means the data that you get from the scanner is not necessarily entirely accurate."
Kyme says previous solutions to this have involved "bolting" a miniature PET scanner to the rat's head so it doesn't matter if the animal moves its head while being scanned.
But he and colleagues have developed a less invasive alternative that tracks and compensates for the movement of the rats.
The rats wear a marker on their heads, which is tracked by two cameras linked to a computer, which then processes the movements and accounts for these in the PET scan.
The researchers showed the system could be used to track the head of a rat while their body was kept still in a tube inside the scanner, or as it was free to move around a small box designed to fit in the scanner.
Kyme says the idea of being able to track a rat as it freely moves around could be very useful in linking behaviour and brain function.
"That's actually very powerful and means that you can do some very interesting experiments that aren't currently possible," he says.
Professor Steven Meikle, who is a co-author on the study, says the new system could be used, for example, to study subtle changes in rat behaviour, linked to schizophrenia.
"At the same time we could be imaging the chemicals in their brain to measure brain function and correlate the two things," says Meikle.