Three clinics in Auckland offer tomosynthesis, one of which, Ascot Radiology, volunteers its frustration at Southern Cross on its website.
"Currently Southern Cross Health Insurance will not reimburse any part of breast imaging that includes tomosynthesis. We understand that this discrepancy in insurer reimbursement is very frustrating for women and we at Ascot Radiology remain in talks with Southern Cross," Ascot Radiology's website states.
Co-founder and managing director of Auckland Breast Centre and Focus Radiotherapy, breast cancer surgeon Dr Erica Whineray Kelly, says she is also irritated by Southern Cross' position and the situation is "completely unacceptable" for Kiwi women.
"We got it [tomosynthesis] January two years ago, we were the first to get it in Auckland and it is excellent," Kelly said. "We get so many small cancers now. We love it.
"It's reducing the amount of ultrasounds we do because we get good images of the breast, it's reducing the number of unnecessary biopsies because we're able to see whether something is benign and we're detecting more cancers.
"They [Southern Cross] have been really difficult with us. They won't allow patients to pay a top-up for tomosynthesis. They won't do any refund for the mammogram if they know a patient has had tomosynthesis, which I think is completely unacceptable."
Going above and beyond the Hippocratic Oath, Kelly has resorted to secretly giving Southern Cross clients free tomosynthesis because she believes they deserve it.
"We haven't told Southern Cross this because we want the flat fee for the mammogram, but we basically provide tomosynthesis for free in our clinic because we don't want people to not get the best technology we can offer.
"We're not getting money for that, but there's no way we're saying 'you're Southern Cross, you're getting that one'."
When contacted by the Herald on Sunday, Southern Cross admitted the technology is an improvement and a policy change has been "recommended" for the middle of next year.
"In May Southern Cross Health Society completed a clinical assessment of digital breast tomosynthesis," Rebecca Ogilvie, Southern Cross network manager, said.
"The clinical assessment found that digital breast tomosynthesis was superior when used in conjunction with a traditional mammogram - ie that digital breast tomosynthesis can aid the diagnosis of patients who have shown abnormalities during a mammogram.
"The overall recommendation from the assessment was that the Health Society formally add cover for diagnostic digital breast tomosynthesis as part of our annual benefit review process in mid-2017.
"When any new technology or treatment is added to the list of benefits under our policies, it usually means a new cost to be borne by members' premiums, which is why we carefully assess the cost and benefits of dozens of new technologies every year - and only provide cover for those that are clinically proven, effective and efficient."
New Zealand Breast Cancer Foundation research analyst Adele Gautier says Kiwis who are able to afford private health care should take advantage of the best technology on offer and the foundation is surprised Southern Cross is yet to accept tomosynthesis.
"Maybe a year ago it wouldn't have surprised us because the jury is still out to some extent. But there are studies that do indicate a very good result for tomosynthesis. We would expect any insurer to be keeping on top of the research, going with it and adopting new technologies," Gautier said.
"If you're in the public screening programme, you don't have a choice and it will be a long time before we see tomosynthesis in public programmes because of the additional overheads. It takes radiologists more time.
"If you're fortunate enough to have private insurance then why wouldn't you go for something that can find more breast cancers?"
The Ministry of Health said it is assessing the use of tomosynthesis, is monitoring research - including the Lund University study - and "a pilot has been performed at one provider, and a review of the required changes in quality control procedures is currently under way."
The Ministry said financial modelling to make tomosynthesis a standard service has not been done.
WHAT IS TOMOSYNTHESIS?
• The latest in breast screening technology, tomosynthesis is used around the world to provide higher accuracy and earlier cancer detection than a standard mammogram.
• Tomosynthesis is an extension of standard 2D digital mammography, which takes multiple images of the breast and creates a 3D image that can be scrolled through by the radiologist.
• Like rounds of bread put together to form a loaf, tomosynthesis takes cross-sectional "slices" of the breast to form a complete 3D X-ray. A mammogram can result in overlapping tissue and make detection more difficult.
• Tomosynthesis scans are done while the patient is in the same machine as for a conventional mammogram, and does not involve as much compression of the breast as a mammogram.
• At around $280, tomosynthesis costs roughly $100 more than a mammogram.