The women are being recalled as a precautionary measure

Bishop Auckland General Hospital, Hexham General Hospital and Friarage Hospital in Northallerton have all stopped using the suspect equipment.

It follows a case in France which suggested the equipment could make some abnormalities difficult to detect.

Health officials have stressed the recall is a precautionary measure.

The 2,224 patients involved had attended clinics at the hospitals because they had suspected breast cancer.

The chance of any pre-cancerous abnormalities in breasts being missed is extremely small Professor Rob Wilson

The recall does not involve women who have been screened as part of the National Breast Screening Programme.

The equipment has been in use at Bishop Auckland since June 2002, at Hexham since 31 July 2003 and Friarage Hospital since 11 November 2003. Women seen prior to these dates, or since 10 June this year are unaffected.

The French case showed the Agfa Embrace CR1A equipment could make certain abnormalities difficult to detect.

In most cases, this particular abnormality, called microcalcification, turns out to be harmless. But in a small number of women, it can be an early sign of breast cancer.

Doctors have stressed that the risk of cancer going undetected as a result of this problem is small.

Professor Rob Wilson, of South Tees Hospitals NHS Trust, said: "The chance of any pre-cancerous abnormalities in breasts being missed is extremely small - but we want to err on the side of caution for the patients concerned."

Robert Aitken, of County Durham and Darlington Acute Hospitals NHS Trust, added: "We understand that women may be anxious about this issue, which is why we will be offering them a further test as soon as possible."

Samia al Qadhi, joint chief executive of the charity Breast Cancer Care said: "We understand that that those women who are being recalled following the withdrawal of this equipment will be anxious and concerned.

"It is important for these women to remember that the risk of cancer not being detected as a result of the problem is small. However, we would urge all of those who receive an invitation for a further mammogram to attend their appointment."

Patients who are concerned or who have changed their address since their last appointment can contact an NHS helpline on 0191 270 5050 for further advice.