Program designed to reduce risk of radiation treatment

Auckland researchers are developing new technology that reduces the amount of healthy tissue cancer patients expose during radiotherapy.

A computer program called Carina can reduce the amount of healthy tissue exposed to radiation by 30 per cent.

Its potential is particularly important in more delicate cases such as brain, neck and prostate tumours, where radiotherapy aims to kill the tumour while limiting damage to surrounding healthy tissue.

Auckland University researchers believe Carina can calculate the best treatment for patients undergoing intensity modulated radiotherapy - often used for more complicated tumours.

This form of treatment allows the radiation beam to be split into smaller beams of differing intensity.

Associate Professor Matthias Ehrgott, from the university's engineering science department, said a treatment plan, based on an oncologist's prescription, must specify the number and direction of the beams and the intensity for each.

"With standard cases, medical physicists know that they will get good results. But it is far more difficult for them to develop a treatment approach in complicated cases where a tumour may be wrapped around, for instance, the spinal cord or the brain stem."

Researchers took data from real hospital cases, ran the information through Carina, and compared it with what treatment planners did in hospitals.

In one case, a patient with a brain tumour received a high radiation dose to 70 per cent of the brain stem under the conventional plan.

In a plan calculated with the software, only 40 per cent of the brain stem received the same dosage.

"If you can reduce the volume of any healthy organ that's exposed to radiation, that's always big progress," Professor Ehrgott said.

"It's impossible to avoid radiation exposure completely because you have tumours usually next to some critical organ."

The treatment planning process was also less time-consuming, said Professor Ehrgott, as the treatment planner did not need to do the calculations manually.

He said the program, being developed with the Auckland District Health Board, needed another three years' work before it would be ready for clinical trials.