Scientists zero in on better radiation Collateral damage: A patient is treated with conventional radiotherapy. Scientists are working on a more focused treatment. For five minutes most days a small part of Sophie's* brain is zapped with a beam of high-energy X-rays. So far she has experienced few side effects from the radiation therapy she receives at a Melbourne hospital, after surgery to remove an aggressive brain tumour three weeks ago. But each time Sophie receives radiation, her face covered with a special mask, she hopes the beam is hitting its target. Game changer: Radiotherapist Katherine Russell treats a patient using microbeam radiation therapy. "When you're having your brain zapped you're hoping it's not doing any more damage than you've already had," she said. Sophie, 42, is one of thousands of people - about one in two cancer patients - whose tumours are irradiated each year. Given the high number of patients who need the treatment, a team of Melbourne clinicians and scientists at the Australian Synchrotron are developing an experimental radiation therapy that better targets cancer cells while reducing the damage to healthy surrounding tissue. A scientist involved in the project, Peter Rogers, said while conventional radiation therapy was effective at killing tumour cells, some normal tissue was also damaged as X-rays entered and exited the body. "That means the radiation dose is really important," said Professor Rogers, who works in women's health at the University of Melbourne. You can cure any tumour you want [with radiation], but that doesn't help if you've irradiated the person so much that they're going to die anyway from the radiation damage. To improve the efficacy of the treatment, the team, which included researchers from CSIRO, the William Buckland Radiotherapy Centre and the Peter MacCallum Cancer Centre, are investigating the X-ray beams produced by the synchrotron's recently refurbished imaging and medical beamline. Professor Rogers said while the experimental technique, known as microbeam radiation therapy, was still several years away from human trials, its unique features were "a game changer" for radiation therapy. The beamline's newly installed magnets could produce up to 10 billion times the X-rays pumped out by hospital radiotherapy machines. The synchrotron's rapid burst of X-rays split into multiple parallel microbeams, smaller than the width of a human hair. Professor Rogers said the advantage of the microbeams was they only affected very small areas of normal tissue that were quickly able to repair themselves. Early experiments on mice tumours found the microbeams caused tumour cells to regress while normal tissue appeared to withstand irradiation. "Tissue repairs from the edge of the wound to the middle so if the wound is very narrow, the cells have only got to divide a couple of times and they've repaired it," he said. A senior scientist at the synchrotron, physiologist James Pearson, said X-rays killed tumour cells by altering their atomic state. "That triggers a set of events that leads to cell death," Dr Pearson said. The synchrotron's narrow beams also meant higher doses of radiation could be administered in a very short time, something not possible with hospital radiation machines. Not her real name.