Over half of medical students and junior doctors underestimate the amounts of radiation involved in regularly ordered scans with 25 per cent wrongly accept that magnetic resonance imaging emits radiation.

Based on the survey conducted by Perth scientist, of third, fourth and final year medical students and freshly graduated doctors, over 10 per cent wrongly considered the ultrasound as a source of ionizing radiation.

An ionizing radiation destroys DNA, and increases the risk of cancer development. A clear understanding about the types of scans that deliver the highest doses, and the ones that are radiation-free is extremely important.

According to the research at the University of Western Australia, 11 per cent of the 340 respondents thought that the knowledge about radiation was either "not really important" or "not important at all".

Even though the interns or graduated doctors who work under supervision answered more survey questions correctly, reaching an average score of 6.9 in the test, as compared to the lower score of 5.7 among final year students, the results of both were still way below the maximum score which was 19.

The findings of this study were published in the Journal of Radiation Imaging and Radiation Oncology. The authors said the results were "of concern".

In an accompanying editorial, Stacy Goergen, the radiology expert at Melbourne's Southern Health added that a total of 430 cancer-related deaths in Australia per year could be attributed to the damaging effect of ionizing radiation stemming from the use of CT scans and X-rays.