CT scan may cause cancer: study

Frequent exposure to radiation emitted from computed tomography, a medical imaging method, could trigger cancer.

Frequent exposure to radiation emitted from computed tomography - commonly known as CT scan - may trigger cancer, suggests a new study. But some experts say people should not be deterred from using it if they require to.

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CT imaging is used to diagnose a wide array of diseases - from brain haemorrhages to cancer in lungs to appendicitis.

During the procedure, X-ray machines rotate around a section of the body, taking cross-sectional pictures that are assembled by the computers into a 3-D image. CT scans can reveal details that do not show up in an ordinary X-ray image.

The researchers said although the CT image is a big improvement over conventional X-rays, the radiation dose that patients receive are also much higher.

"It has been pretty clearly demonstrated that radiation doses in CT scans have increased cancer risk," said study author David Brenner of the Columbia University Medical Centre here.

The researchers estimate that CT scans can cause as much as two per cent of all cancers in the United States alone, in the next 20 to 30 years, reported the online edition of ABC News.

"Although the risk for any one person is not large, the increasing exposure to radiation in the population may be a public health issue in the future," Brenner said.

Radiologists agree that there are cancer risks associated with CT scans, however, they said that no studies have been done to show how great this risk is.

"There is no definitive evidence to suggest the risk is as bad as they state," said Carl Schultz, professor of clinical emergency medicine at the University Of California Irvine School Of Medicine.

"I'm not saying radiation is good. I am saying we have absolutely no idea what the real lifetime risk from CTs is," he added.