The NHS is missing the chance to save money on expensive equipment by failing to collaborate on purchasing and maintenance, a National Audit Office investigation has found.

A report published today looked at how trusts purchase linear accelerator machines – used in radiotherapy treatments for cancer patients – MRI scanners and CT scanners.

Around half of all those machines are due for replacement within three years, at a potential cost of £460m.

The report concluded that “value for money is not being achieved across all trusts”.

The study found that in 2008-09, the range of prices paid for equipment meant that the average cost per CT scan ranged from £54-£268, while for MRI the range was £84-£472. It added that trusts themselves cannot compare costs because the data they hold is not standardised.

A quarter of purchases in 2009-10 were made outside existing framework agreements, the NAO found, further undermining value for money.

Public accounts committee chair Margaret Hodge said: “At a time when the NHS is undergoing radical reform and has the additional challenge of making billions in savings, it is even more important that it focuses on getting the best value for money from all of its assets.”

Her remarks came after a global survey conducted by Siemens Financial Services found the NHS had £2bn worth of “frozen” assets in the form of underused medical equipment.

Siemens found £600m alone was locked up in diagnostic devices, with the remainder of the £2bn frozen in medical furniture and other assets such as endoscopy, dialysis or anaesthetic equipment.

The company’s UK general manager David Martin said NHS capital spending would be squeezed by 17 per cent by 2014-15 and that efficiency goals could only be met if managers invested in the most up to date diagnostic technology.

He added: “Greater use needs to be made of financing techniques that enable such technology to be affordable through monthly payments.”