Flinders Medical Centre Foundation
Flinders Medical Centre Foundation

Radiation



Flinders, Leading The Way In Radiation Research
First Published: Investigator - April 2007
Updated:


Insights into radiation


A team of scientists at Flinders Medical Centre are leading the way in low-level radiation research.


Led by Associate Professor Pamela Sykes from the Department of Haematology and Genetic Pathology, an extremely sensitive test, unlike any in the world, has been developed to detect genetic damage in cells caused by low level radiation.


Current radiation risk assessment is based on the Linear No-Threshold model (LNT) which was established based on the biological effects observed after extremely high levels of radiation. The LNT suggests that all radiation, no matter how small the dose, is dangerous. However, there is a growing awareness that this model needs to be revised.


“There is plenty of evidence demonstrating that high doses of radiation are damaging to cells,” said Assoc Prof Pamela Sykes. “However, we are finding more often that this is not always the case with low doses.”


We are constantly bathed in radiation from our environment, causing cells to be damaged and repaired on a daily basis. The team is looking at different levels of ionising radiation to understand at what point it becomes harmful to contribute toward a better world-wide understanding of what is dangerous.


Until now there has never been a test sensitive enough to accurately measure very low doses of radiation damage so this information has been largely theoretical.


“As with everything we need balance,” said Assoc Prof Sykes. “For example, you will dehydrate if you don’t drink enough fluids but you can over hydrate if you drink too much. In terms of radiation we need a better understanding of what a healthy balance is.”


The Flinders team has attracted substantial support from both the FMC Foundation and outside organisations including a recent US$1.04 million grant from the US Department of Energy to study the effects of low dose radiation.


“There is a lot of fear associated with radiation exposure from medical tests, waste clean-up, nuclear power production and weapons,” said Assoc Prof Sykes. “We are attempting to understand the effects of radiation exposure better to help develop protocols for the management of radioactive materials and devise a better system of protection for those at risk.”


Can low dose radiation be beneficial?


Thanks to the sensitive new test developed at Flinders to study extremely low doses of radiation an interesting change in DNA repair within cells in response to low level radiation has been found.


Thanks to the sensitive new test developed at Flinders to study extremely low doses of radiation an interesting change in DNA repair within cells in response to low level radiation has been found.


It appears that some low doses, in the range of a diagnostic x-ray or an international flight, reduce the level of DNA damage to below that which we get on a daily basis.


Their data also demonstrates that a very low dose of radiation given before exposure to higher levels can reduce cell damage to below what it would be if the initial dose had not been given.


Low dose radiation seems to act as a primer, activating cells to respond better to a dose of radiation that could harm cells.


Investigating radio-protector drugs


Another area of research under investigation, in collaboration with Professor David Grdina from the University of Chicago, is radio-protector drugs - chemicals that reduce the damaging effects of high dose radiation.


Radio-protectors can be protectors, mitigators or both. Protectors are taken prior to radiation exposure and mitigators after.


Amifostine, a drug given to radiotherapy patients to relieve a dry mouth, appears to act as both a protector and mitigator to radiation damage.


A similar drug called phosphonol, which is still in development, is also currently being investigated.


Using their test system, the team have found that amifostine reduces damage to cells to below the background level of radiation damage after a dose of radiation is given equivalent to what emergency workers receive in radioactive “clean-up” situations.


“Developing radio-protectors is important for those who work near high levels of radiation, for example radiation emergency workers,” said Assoc Prof Sykes.


“Understanding radioprotection will also help alleviate some of the fear that the general population has regarding radiological materials.”

 
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