AN investigation into radiation experiments carried out on pregnant women in the 1950s and 1960s has revealed there are greater numbers of cases of thyroid cancer in both men and women in Grampian compared to other parts of Scotland.

There is no evidence to suggest a link with the experiments, but further investigation, where possible, is planned.

In July 1996, in response to a Channel 4 documentary, the Medical Research Council said it would examine the ethical questions raised by eight research studies.

That report is published today. The MRC finds that risk in the questioned studies, from radiation or from other clinical procedures, was very small or negligible and it does not appear that any of the participants have been physically harmed. It says the studies met the research standards of the time, and such standards are now much tighter.

One of the few participants the MRC was able to question was Mrs Kathleen Morrison, now 65, who lives near Aberdeen.

Mrs Morrison, her sister, and three friends were among a number of pregnant women who had radioactive iodine injected into their thyroids to monitor thyroid function and development of the foetal thyroid.

Mrs Morrison fears that children, male or female, of those who volunteered for the experiment in Aberdeen between 1962 and 1964 might be affected.

She suffered thyroid cancer nine years ago, and, although she is not claiming it was as a result of the research, she is concerned about the effects of the work carried out at the Obstetric Medicine Research Unit in Aberdeen, then headed by obstetrician Sir Dugald Baird.

The MRC concedes that ''it has become apparent that some individuals have suffered long-term psychological harm as a result of their participation, for example Mrs Morrison who has harboured concerns about her participation in the study through the 30 years that have elapsed''.

Mrs Morrison, a retired head teacher, said at the time of the Channel 4 documentary: ''I'm absolutely horrified that in 1962 they were prepared to inject myself, a pregnant woman, with radioactive iodine. I feel our trust was betrayed.'' She said they had been told there was no risk involved.

''I was 29. We were intelligent, well educated women, who wanted the best for our children and we agreed to the tests because we never even thought that a doctor would put us at risk.

''They did tell us they were using radioactivity in the tests but nobody knew what that was then. I'm a 'wifie' now and it is not me I am worried about, it is my daughter.''

Yesterday Mrs Morrison said she thought the MRC report very fair, but she strongly believes that Grampian Health Board should make a greater effort to track down the women involved and their children.

''I found I had thyroid cancer quite by chance,'' she said. ''I wasn't unwell, I was very lucky and had the operation nine years ago. My daughter, who took part in the experiment as a foetus, has alerted her doctor and he is now watching out for her just in case there is any risk.

''I would hate to think there were other women out there who were involved but who might not be checking. If there is even a tiny risk and they are checking they may find out early enough.''

Releasing the MRC report Rabbi Julia Neuberger, who chaired the Inquiry Committee, said they had asked Grampian Health Board to check if a follow-up study could be done because it could be reassuring for those who took part, and the wider public.

However such a study was unlikely to be possible because the original research records which would identify all the participants were no longer available.

Dr Gordon Paterson, the Director of Public Health for Grampian Health Board, said he understood and regretted the anxiety caused by the studies.

''The conclusion that the risk from radiation in the studies was very small or non-existent is very reassuring.

''Nevertheless the report has highlighted the fact that there are slightly greater numbers of thyroid cancers in both men and women in Grampian compared to other parts of Scotland and the UK.

''For women this difference is statistically significant but involves small numbers - on average 10 new cases per year.''

He said although there was no evidence to suggest any link between this and the research it did merit further investigation, but expert advice was it was not feasible.

''I think it would be wrong to raise expectations that we could just mount another research study next week but I think the general question as to why thyroid cancer is higher in the North-east is something the research community might well wish to address.''

Clinical trials now require researchers to provide feedback to participants when studies finish and to provide long-term contact points.