A hospital employee has been suspended as University Hospital Kerry conducts a review of over 46,000 scans or files.
The files involve over 26,700 patients in an area that includes Kerry, north Cork and south Limerick.
RTE News reports today that the reports are from the period of March 2016 to July 2017.
The review involves a range of scans including x-rays and ultrasound.
Concerns were first raised during the summer, when three "serious reportable events" were notified regarding a specialist.
An initial audit of a sample of scans was conducted, which since led to a major review of the 46,000 scans.
According to RTE News, six external radiologists are involved in the review and the hospital is currently contacting patients and families through their local GP.
So far, the hospital has reviewed close to 18,000 scans or files.
A total of 21 patients have been recalled, no major missed cases were identified. No critical missed diagnoses have been reported, however some diagnostic errors have occurred.
The South/SouthWest Group, which covers University Hospital Kerry, confirmed to RTE in a statement that it is investigating patient safety concerns at the hospital.
It said that a 'look back' process with independent oversight is underway.
Anybody with any concerns can ring the helpline 1800 742 900, which will operate Monday to Friday, 9am - 5pm.