She was always going to make a mark.

Dr Erica Whineray Kelly is the daughter of a nuclear physicist and the niece of rugby legend Wilson Whineray.

Now this accomplished breast cancer surgeon is roughing up her own professional paddock, trying to bring in new technology to treat cancer in a way, she believes benefits women.

"I want to do the very best for them and it can't be that what we're doing today is the very best we can do."

What she's talking about is a new way of giving radiation, which studies have shown is cheaper, has fewer side effects and reduces recovery time.

It's about women she has treated who talk of having cancer "for two weeks".

It's over "in a blink", says one of her patients.

Intraoperative radiation therapy (IORT) is just one hit of radiation during surgery instead of a course of doses after surgery.

It could be effective for a third of all breast cancers.

But it is fiercely controversial within the field of radiation oncology.

The professional body which sets standards, The Royal Australian and New Zealand College of Radiologists, opposes it, saying it needs more data before IORT can be recommended.

But that's at odds with its own Breast Special Interest Group which supports IORT for selected patients.

Right now, the Ministry of Health is investigating implementing it into the public system.

Dr Whineray Kelly bought the machine to deliver the therapy three years ago, after a pledge she made to a patient to "try harder".

See the full story with Janet McIntyre tonight with on Sunday, TVNZ 1, 7pm.