Hollywood star Angelina Jolie has announced that she had a double mastectomy to reduce her chances of getting breast cancer.

The Oscar-winning actress and campaigner said she hopes her story will inspire other women fighting the life-threatening disease.

Ms Jolie wrote in the New York Times that the operation had made it easier for her to reassure her six children that she will not die young from cancer, like her own mother did at 56.

"We often speak of 'Mommy's mommy', and I find myself trying to explain the illness that took her away from us. They have asked if the same could happen to me," wrote Ms Jolie, 37.

"I have always told them not to worry, but the truth is I carry a 'faulty' gene."

The Oscar-winning actress said her doctors had estimated she had an 87% risk of breast cancer and 50% risk of ovarian cancer.

"Once I knew this was my reality, I decided to be proactive and to minimise the risk as much as I could. I made a decision to have a preventive double mastectomy," she said.

Partner and fellow Hollywood star Brad Pitt was by Ms Jolie's side through three months of treatment that ended late in April, she said. The two got engaged last year.

Ms Jolie said that even though she had kept silent about her treatment while it was going on, she hoped her story would now help other women.

Breast cancer alone kills about 458,000 people each year, according to the World Health Organisation.

It is estimated that between one in 300 and one in 500 women carry a BRCA 1 or BRCA 2 gene mutation, as Ms Jolie does.

Richard Francis, head of research at the Breakthrough Breast Cancer charity in Britain, said it demonstrated the importance of educating women with the gene fault.

"For women like Angelina it's important that they are made fully aware of all the options that are available, including risk-reducing surgery and extra breast screening," Mr Francis said.

Breast Cancer Campaign Chief Executive Baroness Delyth Morgan said Ms Jolie's openness in talking about her experience and her decision to have surgery would raise awareness of the disease and its risk.

Lack of specialist radiographers in Ireland

Minister for Health James Reilly told the Dáil this afternoon that there is "an issue" with radiographers who specialise in mammography.

He said the Government was thinking of reopening a training programme that was closed down.

He was responding after Fianna Fáil’s Billy Kelleher raised the publicity around Ms Jolie's double mastectomy.

Mr Reilly said that there are not enough mammographers in the country and that the Government is trying to recruit from abroad.

He said the current recruitment programme for 15 (whole time equivalent) radiographers was ongoing.

He said 8.3 posts have been filled and five more are close to being filled, while a further 1.8 posts remain vacant.