The micro-dosimeter: One of the project's collaborators, Mark Reinhard from ANSTO, shows off the nucleus-sized radiation-detecting device which is set on a microchip.
Credit: ANSTO
SYDNEY: A tiny device that can accurately measure radiation absorbed by a human cell and predict its biological effects has been developed by Australian researchers.
The nucleus-sized device, called a micro-dosimeter, is the brainchild of medical physicist Anatoly Rozenfeld from the University of Wollongong's Centre for Medical Radiation Physics in Australia.
"It's quite exciting", Rozenfeld said. "We have a … very useful tool that is able to measure the effects of many different kinds of radiation at a cellular level, [and is] able to predict damage in biological tissue. It's a significant breakthrough."
The device was developed in collaboration with researchers from the Australian Nuclear Science and Technology Organisation (ANSTO) and the University of New South Wales, both in Sydney, and with a variety of international organisations, including the National Space Biomedical Research Institute in the USA.
Nifty nanofabrication
Rozenfeld first came up with the idea for the micro-dosimeter twelve years ago, and developed a prototype in 1998. "Now we have produced a sophisticated new generation of micro-dosimeter, based on a silicon chip … using nanofabrication [techniques]," he said.
Sitting on its microchip, the miniscule detector has a volume equivalent to a human cell nucleus. When radiation passes through the detector it leaves behind an electric charge. This charge is then measured and used to calculate the amount of energy the radiation deposited as it passed through the device.
Rozenfeld said that because the gadget is the size and volume of a nucleus, the results can be used to accurately determine the energy deposition that would result if the same radiation passed through a real human cell.
In this way the micro-dosimeter is useful not only in monitoring radiation exposure at a cellular level, he said, but also in predicting the biological effects different types and strengths of radiation are likely to have on human cells.
Aiming high
The researchers believe their device will find a use in everything from cancer therapy to space travel. Its flexibility comes from its ability to address the shortcomings of conventional radiation-measuring devices, the researchers said.
Conventional devices can only measure large doses and limited types of radiation, such as gamma rays. But the radiation encountered in space, for example, is unpredictable and complex, made up of many different types of intensely radioactive particles. With the micro-dosimeter, the energy deposited by each individual particle that passes through is measured; the device isn't limited to detecting only certain types of radiation.
Indeed, the micro-dosimeter has been launched into space aboard a U.S. Naval Academy satellite to determine whether it might eventually play a role in monitoring astronaut safety in space.
Similarly, Rozenfeld said, "the micro-dosimeter could be used to determine the biological doses of radiation pilots [and passengers] in [commercial] aircrafts receive during flight". This would be interesting to see, he said, as at high altitudes atmospheric protection is lessened against a mixture of gamma, neutron and heavy-ion radiation.
Effective doses
In terms of cancer treatment, the researchers believe the micro-dosimeter will be key in understanding and determining effective dose deliveries in new and emerging treatments, such as proton therapy (yet to reach Australian shores).
"In my opinion, in general, micro-dosimetry is important … the technology is great," said Clive Baldock, a medical physicist from the University of Sydney who was not involved in the project.
"[And] in terms of cancer therapy it is particularly important," he said. "It will allow us to better understand what's going on, at a microscopic level, when radiation is encountered … and ultimately this will enable us to design better treatments [for] better patient outcomes."
As well as continuing trials of the micro-dosimeter in medicine, space and air travel scenarios, the research team have their sights set on something smaller in size, but potentially grander in impact: "We're currently working on a DNA-level device," said Rozenfeld.
