Breast cancer diagnostic and screening services across the UK are under threat because of serious staffing problems, experts have warned.
Many experts in breast radiology are planning to retire in coming years and there are also large vacancy rates in the field, the Royal College of Radiologists (RCR) said.
The looming workforce crisis could lead to a "severe" impact on diagnosis of the disease and screening programmes, the College added.
Meanwhile, the UK has one of the lowest number of radiologists in Europe.
And a quarter of NHS Breast Screening Programme units operate with just two or fewer breast radiologists and have no cover for sickness or absence, the RCR said.
The RCR said that a quarter of consultants in breast radiology are expected to retire by 2020 and a third by 2025.
It said retirement rates vary across Britain, with half of those working in the West Midlands planning retirement by 2025 compared with 7% in Northern Ireland.
Overall breast radiology has 8% of unfilled consultant posts, the RCR added.
"The skill of breast radiologists in interpreting mammograms and other complex scans is vital to the early detection and diagnosis of breast cancer as well as in the delivery of cancer screening programmes," said Dr Hilary Dobson, chairwoman of The British Society of Breast Radiology.
"Without more breast radiologists to tackle this increasing demand, we cannot hope to achieve the best possible health outcomes for patients."
Across all radiology services, there are seven radiologists for every 100,000 people living in the UK - which the RCR said is the third lowest of 31 European countries for which this data is available.
The College, which released the figures from various surveys to mark the International Day of Radiology, said that last year the NHS spent more than £88 million on outsourcing radiology services - which could have been used to pay for more than 1,000 full-time consultant radiologists.
The RCR has called on the Government to do more to recruit and retain breast radiologists.
Dr Nicola Strickland, president of the RCR, said: "The International Day of Radiology should be a day when radiologists all over the world celebrate our profession and the tremendous impact radiology can have in improving health outcomes for millions of patients, often saving lives through early and accurate diagnosis of scans and X-rays.
"But it's difficult to celebrate in the UK where we only have seven radiologists per 100,000 people, the third lowest in Europe.
"Urgent investment from the Government and NHS leadership across the UK is needed now."
Danni Manzi, head of policy and campaigns at the charity Breast Cancer Care, said: "Screening is an effective way of detecting breast conditions and breast cancer at an early stage.
"The earlier breast cancer is diagnosed and treated, the more successful treatment is likely to be. So it is depressing to hear that breast screening units are facing such serious staffing problems.
"The NHS Breast Screening Programme has been struggling to cope with demand for a long time and more resource is definitely needed in this area.
"We know NHS budgets are tight, but as the number of breast cancer cases rises, action is needed to address this now."
A Department of Health spokesman said: "We're helping the NHS manage increased demand in cancer services by making staffing a priority, with 20% more clinical radiologists since 2010."
A spokeswoman for Health Education England added: "We recognise the need to train more general radiologists and it is a priority for us to work with partners to find ways to deliver these in the years to come, as we recognise the importance to patients of the diagnostic capability this specialty provides.
"In the short term we would encourage the College, employers and others to seek innovative ways to ensure delivery of specialist breast screening services."