Life science

While drug discoveries attract the media spotlight, medical technology is just as important in the fight against cancer, with body-imaging devices potentially playing a far wider role.

For most people,  cancer research means the development of new drugs to treat the disease. These new drug discoveries are often met with exaggerated newspaper reports heralding them as a potential cancer cure. Much less attention tends to be paid to technology developments designed to help in the fight against the disease, although these can be every bit as vital.

‘Most of the advances you hear about in newspapers are biologically based. You often hear about these therapies very early on, and I suspect if you went back five years later and looked at which had worked you would find there were very few,’ said Prof Peter Williams, director of North Western Medical Physics at Christie Hospital Manchester, one of the largest cancer centres in Europe.

Williams, who is also president of the Institute of Physics and Engineering in Medicine, leads a team of around 60 scientists and engineers, of whom 40 specialise in cancer-related fields. Researchers working within the health service pride themselves on the applied nature of their work, and as a result almost all the team’s R&D results in useful technology, he said.

This contrasts with the essential but more blue-sky research carried out by those working in the biological and pharmaceutical side of cancer treatment. ‘The physics and engineering advances are usually introduced a little more conservatively, so they don’t get out into the public arena until they are very likely to work,’ he said.

In the late 1980s and early 1990s, Williams’ team developed applications for multileaf collimators, devices to shape the radiation beam produced by radiotherapy equipment, to allow them to accurately target tumours of different shapes. Since 1995 these devices have been used on almost every accelerator sold, he said.

More recently, Williams has developed them for use in intensitymodulated radiation therapy, a technique in which computercontrolled X-ray accelerators are used to deliver a precise radiation dose to the tumour, or specific areas within the tumour. The intensity of the radiation beam is controlled to target a higher dose to the tumour while minimising exposure to surrounding tissue.

As the radiation beam can now be modulated to match the shape of the tumour, the next step is to ensure that the dosage hits the target exactly. So Williams is now involved in an international research group attempting to add imaging devices to radiotherapy equipment, to integrate the whole process into a single machine. He is also interested in the use of particle accelerators in cancer imaging.

According to Williams, there is often a lack of connection between those applying science and engineering developments in the health service, and the people at the cutting edge of research in industry and academia.

To help bring the two sides together, the Particle Physics and Astronomy Research Council (PPARC) last week held a forum on the future of medical imaging and radiotherapy in fighting cancer.

‘Without these meetings the academic community tends not to understand exactly what the problems are, and the health service-based community tends to think some things are impossible when actually they are not,’ he said.

This lack of connection is partly due to cost. Particle physics is an expensive area — researchers in the field will think nothing of building a £1m accelerator to conduct a single major experiment — while the NHS is notoriously cash-strapped. As a result researchers have in the past found it difficult to translate their work into devices suitable for the NHS, or even the cash-rich private health service in the US, said Williams.

‘If we develop a new gadget to go on a linear accelerator for treating patients, the assumption is that if it’s good for one patient it’s good for most of them. So you are talking about the health service having to buy 300 to make the technology available to the whole of the UK population. That means they can’t spend £0.5m on a single detector,’ he said.

But research in the field can help to reduce the cost of cancer-imaging devices. Prof Robert Ott, head of radio-isotope physics at the Institute of Cancer Research at the Royal Marsden Hospital, is developing a prototype Positron Emission Tomography (PET) scanner, which is expected to cost less than half that of conventional PET systems.

Ott, who worked in particle physics research in the 1960s and 1970s, is developing the PETRRA system with old colleagues at the Rutherford Appleton Laboratory and technology incubator BTG, which holds the patent.

The system is based on a gas-filled ionisation chamber detector, first developed at CERN by Nobel Prizewinner George Charpak. It consists of two large detectors that can be rotated around the patient to produce a 3D image. ‘Most conventional [PET] detectors will only image small amounts of the body in one go, so they will image your brain or heart, but in cancer detection you want whole-body imaging. We’ve made a detector that can easily do whole-body imaging,’ said Ott.

Advances such as PET imaging have the potential to provide far more detailed information about the nature of an individual’s disease. The technology works through the use of radioactive biomarkers, which are injected into the body and taken up by the tumour. These biomarkers are currently used simply to detect the presence and location of cancerous cells, but researchers are attempting to broaden their range to enable them to provide clinicians with much more information about what is happening at the cellular level.

This means information only available through surgically removing a section of the tumour and analysing it could in the future be obtained noninvasively, said Dr Chris Behrenbruch, president of medical imaging company CTI Mirada Solutions. As well as improving diagnosis, molecular imaging could help to ensure the treatment is effective, he said.

‘You can monitor the response to chemotherapy, radiation or surgery much better. You can see, for example, if there is still residual disease after treatment. It’s a very reactive approach. We want to inject the chemotherapy agent we think will do the job based on the characterisation of the tumour, and as soon as possible if it is not doing the right thing, we will change it,’ he said.

So although technology does not attract the same level of media attention as drug development, its role in detecting and fighting disease is important and expanding. Indeed, molecular-imaging technology could also be used to improve the expensive process of drug discovery itself, said Behrenbruch. ‘The cost of healthcare is spiralling, and if you look at the vast majority of this cost it is in therapeutics. So we need to build better diagnostics to help manage our expenditure on therapeutics.’