Patients in Scotland face delays to vital scans for cancer and other diseases due to a "severe shortage" of imaging agents, experts have warned.

A global shortage of the medical isotopes used in scans of hearts, bones, kidneys and some cancers will cause delays and cancellations across the UK in the coming weeks.

Hospitals in Britain are currently receiving less than 50% of expected supplies and allocations are expected to drop even further.

Last night a Scottish Government spokesman said health officials north of the border were "keeping a close eye on the situation".

"Every effort will be made to maximise any reduced capacity with appropriate prioritisation of patients according to clinical need," he said.

The isotopes are used in more than 80% of routine diagnostic nuclear imaging procedures.

Professor Alan Perkins, honorary secretary of the British Nuclear Medicine Society, said: "The expected number of people who will be affected is quite difficult to determine at the moment but we are certainly talking about hundreds of patients.

"The procedures include cardiac blood flow imaging, bone scanning looking for secondary tumours, lymph node detection in breast cancer and renal function, which is commonly done in children.

"These patients are going to be facing delays. Clinicians will be addressing the issue on the basis of clinical need."

Mr Perkins said doctors would have the option to use alternative tracers or alternative imaging methods, such as magnetic resonance tomography, in some non-urgent cases.

Wolfram Knapp, president- elect of the European Association of Nuclear Medicine, this week warned of a global shortage.

The high flux reactor in Petten, in the Netherlands, was shut down unexpectedly last month after gas bubbles were discovered escaping from a pipe.

A second reactor in France and a third in Belgium are currently closed down for maintenance.

This leaves only two reactors up and running - one in Canada and the other in South Africa.