Health Minister Michael McGimpsey has announced a review of radiology services in Northern Ireland.
It comes after a backlog of X-rays at Altnagelvin Hospital in Londonderry led to four late cancer diagnoses.
One man later died.
Mr McGimpsey said the Regulation and Quality Improvement Authority will review the handling and reporting of radiological requests across all Health Trusts.
"The public must have the confidence in our health and social care services. I want to reassure them that I will do all that I can to ensure that we have the systems in place to prevent something like this happening again."