Health chiefs are reviewing the cases of some 600 Ulster patients in the wake of concerns about errors in scan results at one hospital.
Health Minister Michael McGimpsey confirmed that a review is under way at the Mater Hospital in north Belfast, focusing on 600 diagnostic MRI scans carried out between April and October this year.
It is understood that staff have been drafted in from other health Trust areas to 're-read' the results of the scans which were taken by an independent radiology service.
Mr McGimpsey said the vast majority of scans involved orthopaedic patients. These would include people with injuries and disorders of bones, joints and their associated tissues.
The Eastern Health Board, which takes in the Belfast area, has reassured patients involved they will not have to be re-scanned.
The minister said: "I have ensured that this review will be comprehensive and that its findings will be available as a matter of urgency.
"My first priority is patients. The public deserve high quality, safe health services and I am committed to ensuring this happens."
Mr McGimpsey said he would ensure that "any recommendations are implemented and lessons are learnt" once the review is complete.
"It would be inappropriate to make any further comment until this review is completed," he added.
A spokesman for the Eastern Health Board said: "The Eastern Board, acting on behalf of a range of health and social services organisations, has arranged for an independent and precautionary review of some 600 diagnostic MRI scans at the Mater Hospital.
"No patients will need to be rescanned and this review will be completed very early in the New Year. It would be inappropriate to make any further comment until the review is complete."
The review bears hallmarks of concerns raised about the work of one consultant radiologist at three of Northern Ireland's hospitals two years ago, although is nowhere near on the same scale of seriousness.
More than 7,000 women across Northern Ireland were told in November 2005 that they would have to be reassessed after the quality of the radiologist's work on mammogram checks for breast cancer was queried.
More than 400 women were called back for another mammogram and 19 were found to have breast cancer not picked up in the initial screening. The consultant was suspended.