[ RadSafe ] Very Small Dosimeter
Chris van den Bergen
Christopher.Van-Den-Bergen at adm.monash.edu.au
Thu Mar 6 21:09:24 CST 2008
As Richard Branson gears up to commercialise flights into space, a team
of Australian scientists are pushing new frontiers that could not only
make air and space travel safer but also help in the fight against cancer.
In a world first, Australian scientists have designed and developed a
miniature radiation detector the size of a human cell nucleus. The
revolutionary device called a micro-dosimeter can accurately measure how
much energy is deposited by radiation in the cell nucleus which greatly
assists in the understanding of the effect of the radiation on the cell.
The technology was developed in collaboration between the University of
Wollongong, ANSTO and the University of New South Wales based on an
original concept from Professor Anatoly Rozenfeld of the University of
"This is a significant breakthrough in our ability to successfully
measure different kinds of radiation and accurately predict the cancer
risk of radiation exposure," said Anatoly.
Anatoly explained that conventional detectors are not sophisticated
enough to give accurate readings as they are only designed to measure
radiation in large volumes and only for specific types of radiation,
namely gamma and neutron.
To build a micro-dosimeter, the volume of a cell nucleus, unique
nanofabrication techniques were employed at the Nanotechnology
Fabrication Facility at the University of New South Wales.
"This new technology has significant potential on two important fronts -
for air and space travel where the radiation field is complex,
(containing many different particle types) and for better understanding
the radiation dose people receive during cancer treatments, like proton
therapy," he said.
While proton therapy is still not available in Australia, it is an
emerging cancer treatment that is more accurate in dose delivery, and
hence reduces side effects. Proton interaction is more complex than
conventional radiotherapy. The new micro-dosimeter is helping to
understand the differences in these types of radiation.
While developmental testing of the technology was conducted at ANSTO
making use of the organisation's heavy-ion particle accelerator, the
work of the collaborative team has caught the attention of various
international research scientists.
Dr Mark Reinhard, who is a research leader at ANSTO, explained the
micro-dosimeter was tested in the Massachusetts Hospital, USA. They
placed the micro-chips in a 'human phantom' - and measured the energy
deposited in regions the size of a human cell nucleus.
"These findings will enable radiation oncologists to more accurately
deliver proton treatments to fight cancer cells," Mark said.
The micro-dosimeter is also being investigated by the NASA space program
as one of the major barriers for space travel is cosmic radiation. This
type of radiation is so varied and intense that astronauts can suffer
serious problems from exposure during space missions.
With funding from the US-based National Space Biomedical Research
Institute (NSBRI) the micro-dosimeter was launched on board a US Naval
Academy satellite in March 2007 to investigate how it could play a part
in protecting astronauts from space radiation. The University of
Wollongong and the ANSTO research team are expected to conduct further
tests with NSBRI in the near future.
While space travel for most people might seem like light years away, air
travel is very real. Most commercial flights travel at about 30,000 feet
and radiation is variable with a mixture of gamma, neutron and heavy
ion. Having this type of sophisticated monitoring equipment is important
to further ensure travel safety - especially as we go into the future
where people like Richard Branson will be taking people into space where
ionising radiation levels can vary widely and cancer risk needs to be
measured. Further testing of the micro-dosimeter to monitor modelled
aviation radiation fields is due to commence shortly in CERN, the
world's largest particle physics laboratory in Switzerland.
And for the future, the collaboration sees the micro-dosimeter getting
even smaller! The team is now investigating new types of materials for
fabricating devices that are the size of human DNA.
"We know that radiation can penetrate right through the human body and
can break strands of DNA, the software of life that resides inside a
cell nucleus. If we can model the effects of radiation on DNA level with
the new radiation detectors then we are at the crest of countless
possibilities," Mark concluded.
Chris van den Bergen
Assistant Radiation Protection Officer
Occupational Health and Safety
Building 11, Room S703
Monash University, Clayton, Vic 3800
Telephone: +61 3 9905 1101
Fax: +61 3 9905 2580
More information about the RadSafe