Two patients had a delayed cancer diagnosis when almost 58,000 X-rays taken at Tallaght Hospital in Dublin were not reviewed by a consultant radiologist.

One of those patients has since died and the other is undergoing cancer treatment at the hospital.

Referring to the two known cancer cases in the backlog of X-rays, chief executive designate of Tallaght Hospital Professor Kevin Conlon said: "It is to the hospital’s deep regret that there have been two patients who have had a delayed diagnosis as a result of this.

"One of these persons is under treatment at the hospital for a cancer. The other patient died at the hospital last summer; I was informed of this latter case today and I am pursuing the matter with urgency."

The X-rays were for various tests, including cancer, heart and orthopaedics. There were no X-rays of children in the backlog.

The majority of X-rays would have been reviewed by a non-radiologist which was "totally unacceptable and it arose from systemic and process failures", said Prof Conlon.

The problem came to light when he was appointed on December 14. The HSE and the Health Information Quality Authority were informed that week.

The hospital has since appointed a new head of radiology. In addition, a permanent consultant radiologist was appointed in January and the hospital is seeking approval from the HSE for a further two consultant radiologist positions.

"I now receive a weekly report on progress which just shows a backlog today reduced by 34,752 to 23,169. The backlog will be cleared entirely by May."

The HSE will meet Tallaght today "to consider the options in relation to bringing this process to a conclusion as quickly as possible".

* The hospital has set up a freephone helpline, 1800 283059, for patients and their families who may be concerned. The line is open from 9am to 5pm.