Stephen Evans (Letters, 19 November) argues that the Society of Radiographers has a responsibility to influence choices in the acquisition of high technology.

In his role as the general secretary of my professional body, I agree he has that right. However, I would prefer the society argued from an informed and open-minded position, but this is not the case.

The Plymouth Oncology Centre is able to provide treatment on the most modern equipment thanks to the private finance initiative. From my involvement with capital funding and private finance operating leases I am in a position to comment on both options and I believe the public is best served by the contract we negotiated for maintained equipment, leased for eight years. We have the most up-to-date technology, permitting us to be as accurate as current developments allow. With capital finance, we would probably have had to compromise. It would have limited us to the resources available whenever enhanced software was available.

Our PFI contract imposes stringent financial penalties on the owners if we are unable to treat all booked patients every day. This means that no treatment is interrupted, a significant advantage given that gaps have been shown to reduce the chances of cure for some cancers.

With capital finance, maintenance budgets would have been at the NHS norm of 1 to 2 per cent of the capital value per year. In the private sector, this is usually nearer 5 per cent.

As maintenance is no longer the trust's responsibility, the budget for it will not be subjected to scrutiny every time an overspend occurs, and the cost of providing the service is known. Repairs and replacement parts for linear accelerators can easily be five-figure sums, wreaking havoc in an organisation compelled to balance the books at the end of every year.

Cost per treatment is comparable with other centres which are capitally funded. But at the end of the leasing period, ours is likely to become considerably cheaper as the equipment will be depreciated over eight years instead of the usual 12. This is the opposite of Mr Evans' gloomy prognosis that a high price will be paid later on.

Stephanie McWilliam

Plymouth Oncology Centre

Derriford Hospital