Introduction by Croakey: The Royal Australian and New Zealand College of Radiologists annual scientific meeting (#RANZCR2026) in Ōtautahi Christchurch was an important venue to showcase cutting edge clinical practice in our region and beyond.
But, as convenors told Croakey before the event, it was also an occasion for clinical radiologists and radiation oncologists to focus on how their disciplines fit into the bigger picture of healthcare, and the importance of community, culture and equity for health.
The article below, by Marie McInerney for the Croakey Conference News Service, addresses these themes, discussing a recent advance in medical imaging, Photon Counting CT scanning (PCCT), its rollout in Aotearoa New Zealand, and its planned use in a long-running longitudinal study in the conference’s host city.
It also looks at how to make access to PCCT more equitable – locally, within underserved areas, and globally, in “healthcare deserts” – given its promise of clearer, more informative images and advantageous radiation profile.
Marie McInerney writes:
Leading Harvard Medical School radiologist Dr Rajiv Gupta has carried a commitment to equity from childhood.
The Harvard professor and Vice Chair of Clinical Operations in the Department of Radiology at the Massachusetts General Hospital grew up in a very small village in India.
There were no doctors and no cars. Few of the residents could read, so they would bring their mail and their health concerns to his beloved mother, who was a primary school teacher.
“So, I really know what a medical desert is,” he told Croakey at the recent Royal Australian and New Zealand College of Radiologists annual scientific meeting (#RANZCR2026) in Ōtautahi Christchurch.
“There is essentially no [health] care in those environments.”
Gupta was later surprised to find that similar medical deserts exist around the world, even in developed countries, and particularly in his profession, not always due to a lack of money but through distance, remoteness, and lack of infrastructure.
The disparate availability of healthcare between “deserts” and well-served areas is being borne out right now, for a new and promising development in radiology — known as photon-counting computed tomography (PCCT).
Imaging and equity
Experts and advocates like Gupta say photon-counting technology, which measures X-ray beams one photon at a time to give better and clearer images inside the body, compares to traditional CT scans as a high-definition smart TV does to an old black and white model.
Discovered as an offshoot to the work of CERN, the European Laboratory for Particle Physics in Switzerland and home to the Large Hadron Collider, PCCT has taken more than two decades to develop.
Now five models, including one developed in Aotearoa New Zealand in partnership with CERN and more than 20 partner universities, have been approved for use over the past four years by the United States Food and Drug Authority.
But, because the machines are generally huge, heavy and expensive, they are mostly confined to major hospitals in wealthier nations.
“The question is no longer whether photon-counting works,” Gupta told the conference.
“It is who gets it,” he said.
Slide from Dr Rajiv Gupta’s presentation
Rolling out the technology
Christchurch is currently one of Australasia’s early clinical adopters of photon counting, having rolled out both in-hospital photon counting scanners and portable scanners developed by local health tech company MARS Bioimaging.
RANZCR2026 convenor Professor Anthony Butler, a radiology professor at the University of Otago, told Croakey that PCCT was a big focus at the conference.
Describing photon-counting as “the first new way to measure X-rays in nearly 100 years”, he told Croakey he had invited Gupta, a long-time colleague and collaborator, and others from Harvard to the meeting, to share insights into the technology and available models, and to explore equity issues around access to technology and care.
For disclosure, Butler founded MARS with his father Phil, a professor at University of Canterbury and a Fellow of New Zealand Institute of Physics, so has a commercial interest in the technology.
With expanded access in mind, MARS has developed the world’s first portable photon counting scanner, which gained US FDA approval earlier this year,
The Butlers lead MARS’ team of about 25 people and are planning a trial with the Christchurch Hospital Emergency Department, using mobile PCCT in orthopaedic scanning.
But he and Christchurch are also part of a bigger research project involving PCCT, that is set to get underway and is attracting global interest, including from Gupta’s Harvard team.
Baseline for healthy ageing
With echoes of the beloved ‘Seven Up’ UK documentary series, the landmark 50-year old Christchurch Health and Development Study (CHDS) has followed 1,265 people born in Christchurch in 1977.
One of the world’s longest-running studies of human development, it has been collecting information from its participants since they were infants, looking at health, wellbeing, education, family life, finances and life experiences — creating a database that currently contains more than 60 million data points.
The study checked in with participants every year until they turned 18, and then again at 21, 25, 30, 35, 40 and now 50.
More than 500 research papers later, the program is credited with helping to identify the need for pool fences, anti-smoking legislation, the removal of lead from paint, and the impacts of the 2012 Christchurch earthquake.
Now it is broadening its scope, planning specific health checks for participants’ hearts, eyes and bowels, screening for attention deficit hyperactivity disorder (ADHD), and investigating digital technology use within the cohort.
A member of the CHDS Advisory Board, Butler will lead the radiology scanning for this phase, aiming to create and build a baseline for healthy aging, cardiovascular disease, atherosclerosis, and bone health, in around 800 CHDS participants — “building the world’s first longitudinal photon-counting CT spectral cohort dataset”.
With PCCT’s contribution, the wider CHDS-cardiology program will provide “an objective, population-based snapshot of cardiovascular health in mid-life New Zealanders”, creating an “incredible resource” for the city and beyond, he said.
Butler said the research would use imaging to measure participants’ health as they age across many domains — bone health, peripheral vascular disease, sarcopenia, liver disease, neurovascular disease, and arthritis.
“We’re using the fact that photon counting can do molecular imaging with similarities to PET [positron emission tomography] scans and MRI [magnetic resonance imaging], rather than just traditional CT,” he said.
“That is, we’re establishing what extra/novel clinical benefit comes from photon counting when assessing ageing. This aspect is what Harvard is so interested in.”
Cardiac imaging
According to New Zealand’s Heart Foundation, PCCT has the capacity to produce ultra-high-resolution images of the heart, revealing the fine details of heart muscle, arteries and surrounding fat tissue that traditional CT scans often miss.
It can also be used as a “one-stop shop” for imaging instead of needing multiple scans with different devices, according to Christchurch cardiologist and researcher from the University of Otago, Dr Charlotte Greer.
“Currently, if you wanted to look at someone’s coronary arteries, that would involve a coronary CT or an invasive angiogram,” she said in a Heart Foundation statement last year, when the first PCCT scanners were installed in New Zealand hospitals
“If you want to look at the heart muscle, it might involve an echocardiogram or in some cases an MRI.
“Having a scanner combining all these details at once could mean more patients get seen and get a diagnosis more quickly.”
Butler said he hopes that the CHDS-cardiology study will not only provide valuable point-in-time information, but that it will identify markers for increased future risk of coronary artery disease or heart failure.
The Heart Foundation said researchers know a lot about people who have already been diagnosed with heart disease, but much less about the heart health of the wider population.
That means people at risk, or with early disease, may not be identified until they experience a serious cardiac event, with many having no warning signs.
The study will also aim to investigate how experiences such as stress, financial hardship and difficult childhoods may be associated with poorer heart health decades later.
What photon-counting adds
When speaking to Croakey and in workshop sessions at RANZCR2026, Gupta explained photon-counting in layman’s terms, saying it effectively “turns your black and white CT scanner into a colour CT scanner”.
Being a multispectral imaging system, photon-counting gives much higher resolution than was possible before, he said.
“As a result, the images look cleaner, nicer, more colourful than before, and that gives added capabilities in when you’re making a diagnosis,” he said.
“So, for example, in a stroke patient, you want to know after an intervention is done if there is haemorrhage in the brain – is there bleeding in the brain, or is it just because of the intervention you have some contrast agent that is left over? You can make that determination right away with the photon counting imaging.
“If you have plaque in your coronary arteries, a very common scenario, you can look at the coronary arteries at much higher resolution and characterise the plaque. Is it vulnerable plaque, is it soft plaque, is it calcified plaque? How much of the artery is open?”
In terms of radiation levels, Butler said the technology is “inherently low noise”.
“This gives scanner designers flexibly to either improve image quality at the same radiation dose or, in the case of community photon counting, to maintain hospital quality but use less radiation,” he said.
“Thus, community photon counting scanners can have lower radiation requirements and therefore often be operated in normal outpatient clinics, rather than traditional lead shielded radiology rooms.”
Some technical advantages of PCCT scanning: Slide from Dr Rajiv Gupta’s presentation
Democratising access
Gupta said photon-counting scanners are now used in many countries, but still only account for 0.5 percent of scans globally and are mostly confined to big centres and hospitals because of their cost, size and complexity of installation.
“It can take tens of thousands of dollars just to get the machine into the room,” he said.
“Sometimes they will deliver the machine on a pallet in a parking lot. We’ll have to break the side of a building and hire a crane to lift the machine and put it in…”
There are also “enormous” power and environmental control requirements, he said.
“So these machines are very difficult to work with, in a resource scarce environment.”
That makes it very difficult to share the technology and the benefits to health with smaller and poorer communities, he said.
Thus the interest in portable scanning machines, like the MARS team working to bring PCCT scanning to under-served locations in New Zealand.
Mobile PCCT scanning vehicle: slide from Dr Rajiv Gupta’s presentation
Gupta and his team at Harvard are working on an innovation through the Platform Accelerating Rural Access to Distributed and InteGrated Medical Care (PARADIGM) program, building a small minivan for urgent care to do infusion for cancer patients, undertake blood work, and have a small PCCT scanner on board.
The aim is to serve some of the 60 million Americans who live in what would be described as a healthcare desert, he said.
“We have high hopes for the democratising, if you will, of access to imaging,” Gupta said.
Watch this interview
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