The first patient in England to receive proton beam therapy for cancer is expected to be treated later this month.
The NHS's national cancer director Cally Palmer will tell the Britain Against Cancer conference in London on Tuesday that an NHS proton beam therapy machine will be used to treat a patient at The Christie cancer centre in Manchester.
The hospital's proton beam therapy centre opened earlier this year and its first patient is undergoing preparation for the treatment.
The Christie is the first NHS centre in England to offer the treatment, with University College London Hospitals NHS Foundation Trust due to follow in summer 2020.
When complete they will each treat up to 750 patients every year.
Ms Palmer said: "There have been huge advances in precision cancer treatment which hundreds of thousands of patients across the UK are now benefiting from.
"The first NHS patient undergoing high energy proton beam therapy in England marks a major milestone for the NHS and, as the NHS develops a long term plan for the future, it also marks the end of the first phase of the plans to radically transform cancer treatment across the country."
Roger Spencer, chief executive of The Christie, said: "To be just days away from offering high energy proton beam therapy to patients in the UK for the very first time is really exciting.
"Patients will benefit hugely from having the service available in Manchester, bringing treatment closer for them and their families who currently have to travel abroad, and resulting in less upheaval during what is undoubtedly an extremely stressful time in their lives."
Proton beam therapy is a specialist form of radiotherapy that targets certain cancers very precisely, increasing success rates and reducing side-effects.
It targets tumours with less damage to surrounding healthy tissue and is particularly appropriate for certain cancers in children who are at risk of lasting damage to organs that are still growing.
The treatment has been offered overseas to NHS patients eligible for treatment in England since 2008.
Ms Palmer will also announce that NHS England's GBP130 million investment to upgrade radiotherapy equipment has funded 80 new or upgraded radiotherapy machines.