The radiotherapy error took place earlier this year

Hospital officials say they are "deeply sorry" about the incident, which happened during radiotherapy sessions at Cookridge Hospital in Leeds.

Three investigations are taking place and the results will be shared through the NHS, a hospital spokesman said.

The unnamed patient is continuing to make good progress, he added.

We believe we have taken all necessary action to ensure a similar incident cannot happen again Leeds hospitals spokesman

The blunder, which happened earlier this year, has been described as an "isolated incident" and the hospital has moved to reassure other patients.

The spokesman said: "We are deeply sorry for what has happened.

"The patient was informed as soon as the error was identified and since then we have maintained close contact and are offering whatever help and support we can.

"The trust believes it is vital that all aspects of this incident are subject to thorough, independent and external scrutiny in order to be confident that all the facts are understood, the relevant lessons learned and that people can be reassured over the safety of radiotherapy services.

"We believe we have taken all necessary action to ensure a similar incident cannot happen again."

He said that the hospital would heed any lessons that could be learnt from the investigations.

Trust inquiry

"These lessons will be shared throughout the NHS in general, and the radiotherapy community in particular."

An independent investigation has been conducted by the Inspectorate for Ionizing Radiation (Medical Exposure) Regulations 2000 [IR(ME)R], the relevant authority, which has powers under the Health and Safety at Work Act.

A further review chaired by Professor Mark Baker of the West Yorkshire Cancer Network is also under way.

The trust has also commissioned an investigation.