Medical researchers in Japan say they will start the world's first clinical studies of a radiation therapy using accelerator-based neutron beams to kill cancer cells.

The National Cancer Centre in Tokyo and a Japanese medical equipment maker -- Cancer Intelligence Care Systems -- plan to start the studies using "boron neutron capture therapy (BNCT)" in three years, the centre said.

The BNCT is an innovative radiation treatment which kills selectively without side-effects, but it requires a massive facility including a nuclear reactor to produce neutron beams.

By using a particle accelerator, which is cheaper, safer and smaller than a reactor, it will become feasible for a hospital to provide the therapy on actual patients, the centre told journalists Tuesday.

The centre hopes to try the special on patients with cancers that have been difficult to treat in conventional procedures, such as brain tumors and , it said.