A survey of 14 hospitals across the State has found many of them are trying to cope with significant shortages of radiographers. Some are missing a quarter of the specialists they should have.
At one Dublin hospital, St James's, the shortage there recently prompted management to post notices in its X-ray department advising patients they may encounter delays due to difficulties in recruiting staff.
Mr Thomas O'Connor, chairperson of the Radiography Services Managers/Superintendent Radiographers Association, said at least three of the large Dublin hospitals have "quite significant shortages".
A number of other hospitals around the country were also affected, he said.
"You are talking about places that are down one quarter of their complement at any given time. That is at the extreme but a survey I did recently of 14 hospitals - six in Dublin and eight in the regions - found some hospitals have a full complement of radiographers while others are 26 per cent down on the numbers they should have," Mr O'Connor said.
One of the issues, he said, was getting enough radiographers trained. Up to now there have been only 20 training places in the Republic and not all those who take up places go on to graduate. The number of training places doubled to 40 last September but, as Mr O'Connor pointed out, these will not graduate for four years.
As a result, vacancies are now mainly being filled by Irish people who trained in the UK or by recruiting people from countries such as South Africa where training is similar to that in the Republic.
He said it was difficult to quantify the exact number of vacancies in the State at present but there was no doubt they were having an impact on patients.
"The shortages mean you have to prioritise the workload to reflect the clinical needs of individual patients," he said.
"What you can have is temporary delays where you are giving priority to one area. You balance the problem within the department so no one area specifically is hit," he added.
"We are concerned with any delay. We like to provide a service as rapidly as possible but with restrictions on resources you do your best to ensure there are no unacceptable delays. There are mechanisms to deal with emergencies."
It was getting more difficult to recruit radiographers from abroad as Ireland was not the only country looking for them, Mr O'Connor added. "There are also well-documented shortages in the UK," he said.
Ms Kate Matthews, director of the School of Diagnostic Imaging at UCD, the only institute for training radiographers in the Republic, said it took a long time to get funding for extra training places.
She said part of the problem was her school was funded by the Department of Education but she felt, given that the health service depended on radiographers, it should also make a contribution.
She wrote and telephoned the Department of Health several times since early 2002 seeking a "nominal sum" to support the clinical placements of radiographers but hadn't even got a reply, she said.
"I'm head of the school since 1993 and since 1993 we have campaigned to increase our intake because we could see the shortages coming. We only got approval to increase our intake last year," she said.
The demand for radiographers has increased with the advent of CT, MRI and ultrasound scanning. Breastcheck is also required to be staffed.
Meanwhile, Ms Louise Diamond, president of the Irish Institute of Radiography, said she was well aware of the staff shortages, particularly in Dublin. "It puts a lot of pressure on the staff who remain. They are extremely busy and have to do more on-call," she said.
"It can also impinge on whether staff can be released for further training," she added.
St James's Hospital did not want to comment on the number of vacancies in its radiography department and said it was only one of a number of hospitals affected. After it was contacted about the signs in its X-ray department, the signs were removed.
A spokeswoman for the Department of Health said a broad number of recommendations relating to the training and education requirements of radiographers were "being progressed" and, in this context, the UCD proposal was being considered.