PET scanners are at the cutting edge of medical technology, which means we should all benefit soon, writes Dr Muiris Houston
Many of us can nonchalantly speak of "my MRI scan" or begin sentences with "the CT scan showed . . .", but few of us can claim to have had a PET scan. That's partly because there is only one positron-emission-tomography scanner in the Republic, at Blackrock Clinic in south Dublin, and partly because cutting-edge medical investigations are far from cheap.
All scans reveal what is happening inside us, essentially by showing cross sections of the body or its parts. The principal advantage of PET scans over more conventional technologyis their superior ability to diagnose a range of cancers, including the stages they have reached.
At Blackrock Clinic, which started using its scanner 18 months ago, a pilot study found that PET scans led to a change in the conclusion of how far a cancer had spread in 70 per cent of patients.
When its effect on the medical treatment of 108 patients was assessed it led to a change in management in 72 cases. In other words, two-thirds of patients had their treatment changed for the better as a result of their PET scans.
These figures are highly significant. For patients they represent the difference between undergoing surgery or radio- or chemotherapy, or indeed the type of surgery or amount of therapy they need.
PET's predecessors, magnetic resonance imaging (MRI) and computed tomography (CT), are extremely accurate estimators of form and structure.
PET is different. It produces images at a molecular level, measuring an organ's dynamic state. In short, its ability to track active processes such as blood flow and metabolism enables it to assess the body's functioning at any given time.
PET is based on the principle that most disease states cause increased cellular activity. In cancer, for example, cells multiply and grow at a far greater rate than normal.
When a patient is assessed by MRI scan, it will pick up tumours that have grown to measurable sizes. But carry out a PET scan on the same patient and much earlier disease activity and cancer growth will become apparent, particularly the presence of hitherto unsuspected secondary growths.
A PET scanner is also extremely useful for measuring response to cancer treatment. This can help reduce or avoid the cost of ineffective treatments or unnecessary hospitalisation. The Blackrock analysis estimated that its PET scanner saved €2,615 a patient, even after the substantial cost of using the machine. When added to improved quality-of-life measurements, the cost effectiveness of the new technology is clear.
One would think private patients would gain most when a new facility is introduced to the private health sector, but of 377 PET scans performed last year, 220 - or close to two-thirds - were provided to public patients.
Dr George Duffy, Blackrock Clinic's consultant physician in nuclear medicine and the doctor on whose initiative the scanner was introduced, is quick to emphasise that there is a history of public patients gaining as soon as new procedures are established privately (see panel).
He also points to the narrow range of indications for PET approved by the VHI during its first year of operation as a reason for the unexpectedly low number of private patients who have used the new service.
But Dr Bernadette Carr, the VHI's medical director, says that with one and a half million of the Republic's four million people covered by private medical insurance, the apparently low usage by private patients is in line with expectations.
After reviewing the Blackrock figures, the VHI has just extended the criteria for PET to cover more cancers. It is now applying the same criteria as Medicare, the publicly funded US health insurer.
But the new technology is not cheap: patients without private health insurance can expect to pay €2,650; for those with policies, each scan costs the VHI €1,630 - although Dr Carr says that, with a typical annual premium for Plan B coverage representing just a quarter of the cost of a single PET scan, it is not in a position to offer the new service to its Plan A and B subscribers.
"The VHI is about providing access to the highest-quality and internationally accepted health care. But it is important that this care is provided on an appropriate basis and that everyone gets good value for money spent," she says.
Dr Duffy has a different perspective. "There appears to be a situation that if resources go into the private sector, the Department of Health responds. Based on this premise, I considered that if I could get a PET scanner into Blackrock Clinic, the public system would soon follow."
He estimates that, based on one scanner per million population, the cost of each multimillion-euro machine would be quickly recouped through improved efficiency and reduced waiting lists.
It is to the credit of the chief executives of certain public hospitals that such a high percentage of PET scans have been funded from the public purse. Dr Stephen Lane, consultant respiratory physician at the Adelaide & Meath Hospital, in Tallaght, has used PET in the management of 23 patients with lung cancer.
"Most of these were public patients, and I have found the CEO of Tallaght, Mr Michael Lyons, very helpful in sanctioning these scans at Blackrock Clinic," he says.
Dr Lane describes how PET helped avoid unnecessary surgery on a 54-year-old patient with lung cancer by correctly identifying how far it had spread.
When she developed chest pain, the scan helped identify its cause as spread of the tumour to her ribs, helping Dr Lane decide on the correct treatment. And although her prognosis is poor, he has no doubt that PET was instrumental in improving her clinical management and the quality of her life.
Private medicine has repeatedly led to improvements in our public hospital services.
In 1964, the Republic had no dialysis facilities for people with kidney failure. Three consultants in Jervis Street Hospital in Dublin, Prof Billy O'Dwyer, Dr Joe Woodcock and Dr Andrew Barry, bought an artificial-kidney machine and made
it available to patients at the hospital. Their initiative meant the State's kidney-disease facilities caught up with those available in the rest of the developed world. The Jervis Street private initiative was taken over by the Department of Health and Children, and today we have one of Europe's best public renal-dialysis services.
With MRI scans now regarded as routine within the health service, it requires a gentle jogging of the memory to recall the slow introduction of MRI machines. The Republic's first MRI scanner was bought by Mater Private Hospital in 1987. Dr Joe Ennis, consultant radiologist at the north Dublin hospital, must be given most of the credit. Scans were initially
available to private patients, who were reimbursed by the VHI. Some years later, the Department of Health installed a public-system
MRI scanner in Beaumont
Hospital. We now have more than 20 MRI scanners, helping to improve
the management of cancer,
heart disease, orthopaedic problems and infectious
diseases.
Standards have also been raised in radiotherapy services. Even though we had two units for public patients, at St Luke's Hospital in Dublin and St Finbarr's Hospital in Cork, their equipment became old and somewhat outdated. The Mater Private and St Vincent's Private hospitals invested in two new privately funded radiotherapy suites. In response to the quality of the new facilities and increased waiting times in the public sector, non-paying patients were referred to the two private hospitals. Eventually the Department of Health and Children provided St Luke's with about €32 million for new equipment and services.
As it introduced PET scanning to the Republic, Blackrock Clinic faced an additional challenge. An hour before their scans, patients have to be injected with a radioactive sugar called fluorodeoxyglucose, a marker substance preferentially taken up by cancer cells, right (and, far right, once the patient was in complete remission). It loses its radioactivity rapidly, however.
The solution hit upon by Dr George Duffy, the clinic's consultant physician in nuclear medicine, was to form the Molecular Imaging Institute, a company to build a production facility next to the PET scanner. Effectively a mini pharmaceutical plant, it is supervised by Dr Ruari O'Donnell and a team of radiochemists and pharmacists. Operating under strict licence from the Irish Medicines Board, this high-tech facility starts working at 3 a.m. each morning to produce the radioactive sugar required by the day's patients.
Funded by well-known businessmen led by Alastair McGuckian, of the Masstock agribusiness company,the Molecular Imaging Institute now also supplies the new PET scanner in Belfast. The initiative means that if and when the Government commissions additional PET scanners, it will have a ready source of the radioactive marker.