Cancer Treatment: proton beam therapy coming to UK 

by Sharon Ann Holgate
Published in E&T April 18 2016 online, and in the May 2016 print edition 

    Hidden behind hoarding on Grafton Way, near Tottenham Court Road in London, a building is taking shape that will house a revolution in patient care in the UK – a high-energy proton beam therapy centre. Read more....

Include or Lose: Design for the whole market

by Sharon Ann Holgate
Published in E&T March 14 2016 online, and in the April 2016 print edition

    Ever had trouble shaking ketchup out of a glass bottle? Now imagine struggling to unscrew the lid of a marmalade jar every breakfast time because you don’t have the strength to grip it firmly enough. Read more....

New technologies in medicine

by Sharon Ann Holgate
Published in E&T November 8 2010 online, and in the Nov 2010 print edition

As the NHS faces a funding gap of £6 bn a year by 2015, E&T looks at the new technologies for better and less costly medical treatment of the UK's increasingly infirm and ageing population.

     If we're honest, going to the doctor is up there with having teeth filled, completing our tax return, and other tasks that we know we must do, but would rather not. So it will probably be a relief to learn that emerging technologies could spell an end to at least some hospital and GP appointments, of which there are about 300 million in the UK each year (and 40 per cent of those, according to some sources, are unnecessary) while at the same time potentially cutting waiting lists and saving healthcare services money.

    One evolving area is software that can carry out online patient interviewing prior to a visit to the GP. 'Computer-patient interviewing will develop over the next few years, and should make consultations more efficient,' says Ray Jones, Professor of Health Informatics at Plymouth University. 'If the interview makes it clear what is needed, the GP might not need to see the patient at all, or might be able to carry out the consultation via telephone or Skype. Also a lot of research shows patients are happier revealing embarrassing things to a computer than to their GP.'

    Jones also sees the Internet being used more for both self-care (see 'DIY Healthcare' boxout, p25) and for remote group consultations, as in current US projects where clinicians run websites for groups of diabetics. 'Where you get clinicians involved, you could probably see a reduction in the number of face-to-face consultations, which in remote areas would have major implications for global warming by saving a lot of travel,' he says.

No therapist required

     New computer-based solutions are also being explored for mental health problems, including anxiety and depression, which when combined form the most common mental disorder in Britain affecting almost 9 per cent of the population. 'The size of the problem of depression and anxiety is far greater than could be effectively treated with therapists,' says psychologist Dr David Purves, who has designed the 'Blues Begone' computer software package to help address this issue.

    The program is based on Cognitive Behavioural Therapy (CBT), a proven method of helping people stop underestimating their strengths and overestimating threats. Unlike the previous generation of software used to deliver CBT, Blues Begone - which has been adopted by some UK local area health authorities - assesses the user via a questionnaire, then tailors the self-help exercises to fit by drawing on a database of 306 different program elements. A talking computer animation of Purves helps guide the user through the tasks selected by the program, while further animated characters describe their problems in case studies. Throughout the treatment, telephone contact by mental health workers helps keep people engaged with the program, which constantly monitors progress via built-in evaluation tests.

    'In truth, all psychological treatment is self-help. So you have to empower the client to get the best outcome, and we need electronic systems that people can access and so help themselves,' says Purves, adding that in a recent study Blues Begone cured 60 per cent of patients with depression, and 50 per cent of anxiety patients. 'The World Health Organisation say that by 2020 depression will be the second largest burden of disease in the world. This [sort of technology] is something you can just scale up and deliver when people want it.'

Monitoring technologies

     Another way to reduce the need for medical assistance is to prevent avoidable accidents, such as falls, from happening.

    Falls have a tremendous impact on the UK healthcare system, as 30 per cent of the over-65s have a fall each year, costing the NHS over £1bn - and, more importantly, lives.

    'Half a million elderly are at risk of falling, and the majority of falls are due to an abnormal gait,' says Dr Diana Hodgins from European Technology for Business Ltd, designer of the Pegasus gait analysis device featured in 'A Question of Balance' (E&T Issue 17, 2009).

    This small, strap-on device sends data from inertial measuring units to an ordinary PC or laptop and enables a gait analysis to be performed in under 10 minutes at a GP's surgery. 'Our goal is to quantify their gait (by measuring joint angle, stride duration and variability and phasing between the limbs) so they can be given an exercise regime to take them off the 'at risk' register. Everybody has got to look more at how to save money in the NHS, and the best way is early and correct diagnosis,' continues Hodgins.

    Monitoring technologies can also help with rehabilitation. The main aims of Activ4Life's Pro V3.8 orthopaedic activity monitoring system, for example, are quicker hospital discharges, fewer post-operative visits to clinicians and an early detection of complications following hip and knee replacements.

    The system consists of a wristwatch-sized monitor, attached with double-sided medical sticky tabs to the users' waist, and a docking station that receives encrypted data from the monitor's 2D accelerometers. Each night, the monitor is recharged in the dock, while the encrypted acceleration patterns that reveal if a user has been running, walking, shuffling or taking the stairs are sent to a secure server via the mobile phone network, along with the patient's report on how much pain they have been in.

    By comparing the new data with a profile in the database (built up from results of ongoing trials) that matches the age, gender, BMI and post-operative state of the patient, a prediction is made of either degeneration of their condition or improvement. Exercise regimes are then suggested to optimise recovery, and try to stop people doing too much too soon and undoing their operation, or worse still not moving at all.

    'The device shows patients what their daily activity has been and tells them what their clinician has indicated they should do,' says Dr Ian Revie who designed the system. 'Self-management encourages the patient to be less poorly, and we've shown in our trials that the clinical outcome for patients is 10-12 per cent better, if they are monitored.' In addition, Revie's estimates suggest standard use of the monitor would save at least 20 per cent of the current cost of treating each patient. 'The more treatments can be done in a remote fashion that we don't really need to see a doctor for, the more clinicians can focus on complex diseases,' says Revie.

    Vital signs, such as blood pressure and pulse, can also be remotely monitored, and could play a role in managing patients with long-term disease.

    The Mayo Clinic in the US (in collaboration with GE Healthcare and Intel) is half way through a year-long study to evaluate the effectiveness of in-home monitoring technology - which includes videoconferencing capability - in reducing hospital visits for patients with chronic health conditions. The hope is that detecting deterioration in a patients' condition at an early stage will enable prompt treatment that reduces the need for hospitalisation. An existing teleheaith service in the USA has alreday reduced hospital admissions by 20 per cent.

Specialist care

     Videoconferencing has been used as part of e-health for years in countries such as Norway to provide consultations with dermatology specialists, located many miles away. It can also allow staff from different hospitals to have 'virtual meetings and so save on travel time and costs. The South West Wales Cancer Network showed during evaluation of their videoconferencing use that one site saved £5,100 in travelling expenses in just a month.

    In pathology, not only is technology enabling access to specialists, it is also helping address a deficit of qualified staff. 'There is a severe shortage of pathologists in most parts of the world, including Japan, Canada, Australia, New Zealand and the UK,' explains Dr Jared N. Schwartz MD, former president of the College of American Pathologists and chief medical officer of digital pathology systems suppliers Aperio Technologies. 'So these countries are increasingly adopting a new technology, called 'whole slide scanning' where you scan the tissue sample on a slide and end up with an identical digital microscopic image of what you would have seen, had you been looking through the microscope.'

    This scan does not suffer distortion during transmission, so can be sent to another location either via a secured network or over the Internet as long as patient identity is protected. This not only helps hospitals with no pathology staff on site, but provides access to pathologists specialising in particular areas, such as neuro-pathology when a second opinion is required, without lengthy delays and potential risk of loss or damage when mailing samples. In the future, digitising slides could reduce the need for storing the original samples for years, which Schwartz says 'would save significant space and money'.

    Digitising the slides also enables computer-assisted diagnostic tools to be used. In general, pathologists are looking for a particular pattern or cell type within a tissue sample. Finding these specific cells involves looking through a microscope at hundreds of them, and the results are bound to be subjective. 'Five pathologists might give three different opinions, but a computer-assisted algorithm that counts thousands of cells may give the pathologist a statistically more standardised result,' says Schwartz. 'One of the hopes is that by using computer software that will improve over time, there will be increased standardisation of diagnoses, and we can be confident that our interpretation is more accurate.'

    Despite predicting a range of new computer applications to help pathologists diagnose and forecast the progress of diseases, human analysis will not be eliminated in the foreseeable future, says Schwartz. 'I am optimistic that we will continue to have extraordinarily well-trained physicians to make sure the technology makes sense. No technology is foolproof, and when you're talking about people's health and lives, you are still going to have to have somebody to make sure all the results fit into what you're seeing from the patient.'

Ease of access

     Some developments in e-health are just a matter of adapting existing technologies for use in a healthcare setting. In Australia, for example, the government has announced the introduction of personally controlled electronic health records and is working towards electronic prescribing and dispensing of medicines, which should increase the time healthcare professionals can spend with patients.

    'When you're looking at what technology we should be encouraging, you're saying: what do the majority of patients want that can enhance what we know and delivers the best quality of healthcare for the best cost?' says general practitioner Grant Ingrams, chair of the British Medical Association's GP IT committee. This doesn't have to be high tech. 'I think telephone consultations and email will become more common, but in addition to normal consultations - which have gone up by a third over the last 10 years and continue to rise. So we've got to look at how to be more efficient, and these things might help,' explains Ingrams.

    He finds email particularly useful, if he needs patients to record regular measurements of things, like blood sugar levels, then send them to him for review. 'It's a fantastic way of doing it because it means they haven't got to wait for me to have an appointment free to talk to them,' says Ingrams.

    One feature of all these advances is the human intervention required, so the idea of being cured by a 'virtual doctor' is likely to remain science-fiction for some time. 'I still need to read and interpret any information, and the majority of patients prefer to see a doctor above any other type of service,' concludes Ingrams.

© IET. Reproduced with permission.

Home help

by Sharon Ann Holgate
Published in E&T online on 5 October 2009 and in the vol 4 issue 17 print edition

Technologists have come up with a kitchen that keeps an eye on Alzheimer’s sufferers, and bracelets that monitor blood pressure. But will people wear them or reject them? E &T asks the question.

    No one likes to think too deeply about ageing, or about the disabilities we might have in the future. But whether we like it or not, by the time most of us reach old age we will be having difficulties carrying out tasks we used to take for granted, and technology might provide the only solution to some of the care we need.

     “As a society we are getting older. Over the next 30 years the number of people over the age of 65 is going to increase dramatically compared with the number between 18 and 65,” says Helen Petrie, professor of human-computer interaction at the University of York. Originally a psychologist, Petrie now evaluates technology for people with disabilities and the elderly.

    “It’s not that it would be nice or interesting research-wise to use technology to help support people; we are going to have to, because there just won’t be enough younger people around to care for the elderly,” she says.

     Although we are all likely to need some help in old age, anyone suffering with dementia will need more specialist assistance. There are currently 700,000 people in the UK living with the condition, with one in 20 people above 65, one in five of the over 80s, and one in three of the 90-plus age group affected.

     A variety of electronic devices have already been developed to help. These include sensors that can detect whether a chair or bed is occupied, valves that automatically cut off the gas supply in the event of a leak, and a system that switches the bathroom light on when a person gets out of bed at night. All aim to make the home a safer environment for vulnerable people. “But take-up has been less than we initially thought it would be,” says Professor Dawn Brooker, director of the University of Worcester Association for Dementia Studies.

     “For diabetes, or heart-care, people are used to relying on little gadgets or things to deliver medicines, whereas in dementia care there is no history of that. So getting care staff and family members to think about technology as helpful is a bigger leap for people to make,” she explains. “Then there are the ethical issues. In many cases you are working with people with limited capacity to make informed choices. So if you want to introduce a gadget that, say, helps track where people with dementia are or does things for them, I think that makes people uneasy and back away from using technology where it could be helpful.”

    An electronic blood pressure monitor that transmits readings wirelessly is just one example of a new technology that could be seen as quite invasive. But Brooker thinks the accurate picture of symptoms they give is useful. “Typically if you interview a person with dementia about their health they will say they are absolutely fine, although they may be having quite big problems. They’re just not remembering that they have,” she explains.

Electronic tagging for dementia

     More controversially, there are also electronic tagging systems beginning to appear in the UK that can track the whereabouts of users. The United States and Sweden have already rejected some tracking devices because they feel it infringes on a person’s rights.

     “The whole issue of privacy and monitoring is a very personal one,” thinks Brooker. “If you look at how people feel about identity cards there is a huge divide. Some people will go on protests about them, while other people think ‘It’s okay, I’ve got nothing to hide’. You are likely to see that same span of opinion in people who’ve got dementia.”

     Many of the electronic assistive systems undergoing development involve transmitting data from sensors wirelessly to a computer, and so effectively allow the user to be remotely monitored. “Elderly people don’t like the idea of being watched by some sort of Big Brother, but as younger people that are used to electronics get older they will probably find this sort of technology more acceptable,” says sheltered housing officer Joe Edmondson.

     But what happens if we reach a state where we are no longer capable of expressing our opinions? Brooker says early diagnosis of dementia is key so people can decide on the level of monitoring they find acceptable while they still have the capacity to make a choice. Petrie echoes this view. “People need to make informed choices while they still can, and set limits. I think the problem with British society is we are a bit nervous about facing these things full on, as we’ve seen with euthanasia,” she adds. “We have to stop being squeamish.”

     Hospice nurse Emma Dennis says their standard practice of recording what care people would like as their health deteriorates “definitely eases the burden on the family, and is something we find very valuable too.” She can see the benefits of a similar procedure for assistive technology, but warns, “people sometimes change their minds along the way, so they might need to review their decisions.”

     In some cultures, the whole idea of elderly people living apart from their families and relying on assistive technology is totally unacceptable. But even among older folk who are used to living alone, some technologies have met with a negative response. “Older people with dementia can wander out of the house, and there was an attempt to record messages from an adult child saying things like ‘Mum, please go back to bed, it’s the middle of the night.’ People were completely freaked out by this,” explains Petrie.

     According to Brooker, in the early stages of dementia, when memory loss is common, people are generally willing to try technological aids, “however there is a lot of stigma that surrounds dementia and stops people seeking help”. Petrie feels we have good reason to form such attitudes. “We know deep down that our society is not very tolerant to people who are different in any way, so we don’t want to draw attention to ourselves as being disabled,” she explains.

     “So much depends on the character of the person,” adds Dennis. “Some people will accept any aid if they feel it is going to help them and their family, as I think many people have a fear of being a burden. But some people are totally against even considering something as basic as a walking stick. They see it as a constant reminder to them and the outside world that they are becoming more frail.”

     Edmondson also thinks people’s acceptance of their disability will affect take-up of new technologies. “Specialist aids such as the flashing lights on doorbells that alert deaf people tend to be readily accepted by users because they can immediately see the benefits. I feel people familiar with these sorts of devices would be more likely to accept new electronic healthcare technologies than someone who has not used anything like this.”

     One rather surprising reaction is people becoming very attached to assistive technology. When a care home recently installed a wireless tracking system for example, the residents decided to personalise the modules they had to wear by decorating them.

Fear of technology

     It is easy to believe that the elderly will, almost as a matter of course, reject technology. But that is becoming less likely. “People who are in their seventies and eighties now probably didn’t use computers at work very much. But as we age we will expect to keep on using technologies, and will think more of technology as a solution to our problems,” says Petrie, swiftly adding that the popular belief that the current older generation have an inherent fear of technology is nonsense.

     The key, she says, is to relate new technologies to things pensioners are familiar with, like telephones, dictating and typewriters. When Petrie introduced groups of older people to voice input technology – a much more accessible option for people with arthritic hands than a keyboard and mouse. “They loved it,” Petrie enthuses. “They said: ‘We never knew this existed, what a wonderful idea. Why can’t we use a computer this way?’”

     Petrie is currently researching whether virtual personal assistants or companions would also be useful for older people living alone.

     “Part of what a virtual assistant could do would be to encourage you to go out, or to Skype your children or friends, so it would help you keep in touch with real human beings,” she explains. “You could have a purely software system with an avatar on a TV or PC screen. Or would people prefer it was a physical thing that sat on their kitchen table and talked to them?” One mainstream example of the latter that Petrie is studying is the Nabaztag electronic ‘smart rabbit’. The plastic pet connects to the Internet and can carry out a range of tasks including reading website content and blogs, giving news or weather information on demand, and telling you when emails have arrived.

     “I think this is the future,” says Petrie.

     The idea that any form of electronic assistant or monitoring could be misused to replace human interaction does, however, cause anxiety. “People need people primarily,” says Brooker, “and I think the biggest danger is that we use technology to take the place of human contact and kindness, and that it is seen as a cheaper alternative to having staff visit people.”

     “It could mean staff sit in a control room looking at a monitor,” Edmondson points out. “What the residents [of sheltered housing schemes] need is company, and people to see them on a daily basis. They don’t want to be ruled by machines.”

     Petrie, who advises designers of new assistive products, as well as Web designers, firmly believes the issue of accessibility for all is a challenge rather than a problem. She does however acknowledge there are some issues to be addressed, particularly when it comes to specialist aids.

     One of the biggest problems, says Petrie, is that designers go too far through the design process without consulting the likely users. Alternatively, they design something for just one disabled friend or elderly relative only to discover it does not provide a solution for anyone else. To help combat this, the Foundation for Assistive Technology, for which Petrie is a trustee, is currently setting up a user-panel of people of different ages and with different disabilities to act as testers for new products and take part in focus groups. It is vital for engineers and technologists to have access to “a broad range of information from an appropriate spectrum of people,” says Petrie.

     Looks are also important. “There has been an unfortunate tradition of thinking aids don’t have to be attractive,” continues Petrie. “Because we live in a very consumer-aware age you need to make assistive technology look really cool.”

    However it is equally important for things to look familiar. This was one of the main aims of a University of Newcastle project to design an ‘Ambient Kitchen’ for people with dementia.

    Newcastle is one of three research hubs announced in April this year – the others being based at Aberdeen and Nottingham universities – to develop digital technologies to transform the lives of the elderly, disabled and isolated.

     Although it looks exactly like an ordinary kitchen, the Ambient Kitchen is computer-controlled and has sensors in utensils, cupboards, appliances, work surfaces and the floor. Users see prompts projected onto the wall they are facing if they stray from a pre-set ‘recipe’ they are following.

     “One of the things I say to health and social care providers is if you get a service right for somebody with dementia, you’ll get it right for everybody else,” concludes Brooker. “I’ve sometimes been in hotel bathrooms where I think ‘Where’s the basin? How do I get some soap?’ But if you are designing a bathroom for somebody with dementia you have to make sure it looks like the sort of bathroom we all had as children. That will be a bathroom everybody can use without feeling stupid, and the same goes for technology.”

 © IET. Reproduced with permission.

Towards a less claustrophobic scanning

by Sharon Ann Holgate
Published in E&T online on 5 October 2009, and in the vol 4 issue 17 print edition

 E&T investigates some of the latest 'open' MRI scanners and finds out what benefits patients and doctors can expect.

    It is unlikely anyone undergoing a magnetic resonance imaging (MRI) scan would describe the experience as pleasant. Having to lie very still in a narrow tube for anything up to an hour, while the machine loudly bangs its way through the scanning procedure, is hardly fun. In fact, some patients find it so traumatic they have to be sedated - at times, put under general anaesthetic - before being scanned. That is if they can fit inside it at all.

    However, claustrophobia and a tight squeeze could soon become problems of the past as more of the latest generation of 'open' scanners, with very wide bores or completely open gaps for the patient, appear in clinics around the world. These systems also offer the potential for MRI-guided surgery.

Wider bore systems

    According to the World Health Organization, there are at least 300 million clinically obese adults worldwide, so not surprisingly this has been a driving factor for developments in scanner technology. Siemens, for instance, have been producing scanners with wide bores - 70cm as opposed to the standard 60cm - since 2004.

    "We see a trend towards more patient comfort. Growing obesity will push this trend, and patients are better informed than they used to be - they look on the Internet and pick an institution. So with an ever higher density of MR systems in the world, our customers are in a competitive situation," says Mathias Blasche, principal key expert in the MR Business Unit of Siemens Healthcare. Children, intensive care patients, or anyone dependent on medical equipment can also benefit from wider bores, explains Blasche. "We see better image quality with anxious patients who are prone to move during the scan if they do not feel comfortable," he adds.

    All patients can gain from these developments. Siemens's new wide-bore Magnetom Espree-Pink breast scanner, for example, allows spectroscopy and biopsies to be carried out in situ, aided by dedicated software and a specially designed coil (see 'How MRI works' p22) that can be adjusted to optimise scanning of any breast size.

Don't take it lying down

    Some conditions, like certain back injuries, can actually be made worse by patients lying flat on their backs in a conventional scanner. In open scanners they don't have to.

    At the Nuffield Orthopaedic Centre (NOC) in Oxford, where they installed a FONAR 360° open scanner in a purpose-built building in 2006, they can now scan patients lying on their sides. Their scanner also accommodates larger patients and has seen the number of people requiring pre-scan sedation fall from roughly one a week (when using a conventional scanner) to one every two months, says Ruth McDonnell, MRI lead radiographer at the NOC.

    "Patients are often relieved to find the scanner is not a tube like they've seen on TV. Being able to see out of the scanner throughout the examination makes them feel much less enclosed," explains McDonnell. Philips's patient studies echo this experience: their Panorama HFO open scanner reduced the rejection rate by claustrophobic patients by a half.

    Systems like the FONAR UPRIGHT multi-position scanner take the idea a stage further. "It can scan patients upright in weight-bearing positions, in positions of pain, and in positions of flexion, extension, lateral bending and rotation," says a spokesperson for US-based FONAR. Patients can also be scanned sitting upright or lying horizontally. This provides a new route to diagnoses for doctors and physiotherapists, and is particularly valuable for spinal problems that can look significantly different when lying down.

    Italian manufacturers Esaote, who produce dedicated musculoskeletal scanners, allow study of joints and the spine in weight-bearing positions via their G-scan. As the whole unit can be rotated from horizontal to vertical, the scan can be performed at any angle. In their most open system, the C-scan, the patient inserts the joint to be studied while the rest of their body is outside the machine.

The technical challenge

    Open and wider-bore MRI machines may seem like an obvious step that should have been taken years ago. However, the technical challenges involved in obtaining a high-resolution image from these systems has been considerable. For a start, in order to get a clear MR image the magnetic field provided by the scanner magnet needs to be uniform - and the shorter the magnet, the more difficult this is to achieve.

    "We addressed this by developing a [superconducting] magnet with seven field-generating coils instead of six," says Blasche from Siemens, who specialise in wide bore scanners. This gave a field uniform enough to image any organ in a single step, despite a short 125cm system length. Siemens also worked on improving the perfor-mance of the radio-frequency (RF) system and RF coils that create the pulse required to obtain an MRI signal, as the more RF channels available, the higher the signal-to-noise ratio and the faster the imaging.

    Meanwhile, new types of receiver coil have had to be developed for completely open systems to obtain good image quality. "The rule in MRI is that the axis of symmetry of the receiver coil needs to be perpendicular to the orientation of the main magnetic field. Conventional high-field superconducting MRI systems have a horizontal magnetic field that is parallel to the long axis of the body, so they can use planar (flat) coils to image the spine. The open MRIs operate with a vertical magnetic field and use solenoidal ('wrap-around') receiver coils," explain FONAR. 

    As truly open scanners have a gap between two magnet pole-pieces, a new 'iron-frame' technology was also needed to provide a suitable magnetic field. This forms the basis for all open MRI scanners. Iron-frame technology uses iron to provide a conduit for the magnetic flux to complete its circuit from the north pole of the magnet to the south pole. In the FONAR 360° scanner, it is partly built into the scanner room walls.

The surgery of the future?

    Open scanners lend themselves to MRI-guided surgical procedures, known as 'interventional MRI' - something currently in its infancy. The hope is that complex surgery, including the removal of cancerous tumours, could be performed under MR guidance making it more accurate. But there is a catch.

    Many metals are strongly attracted by the large magnetic field generated by MRI scanners, so surgeons cannot use conventional surgical instruments. "A scalpel must be sharp, but if it cannot be made from a ferromagnetic or conductive material, what material do you use? Interventional MRI is not just an engineering challenge, but a challenge for materials scientists too," explains Steve Keevil, senior lecturer in Imaging Sciences at St Thomas' Hospital in London.

    Guy's and St Thomas' Hospital has carried out MRI guiding of cardiac catheters since 2001 using a conventional scanner. "We have been restricted to using devices that are MR safe by chance," says Keevil. Meanwhile, the NOC have conducted preliminary research into interventional procedures using their open scanner. "However, there have been limitations including the supply of MR-safe needles suitable for interventional musculoskeletal work," says McDonnell.

    While some specialist devices, such as biopsy kits and needles produced by DAUM, do exist there are few general instruments available. Significant investment will be required to develop new products and get them through all the regulatory tests, then, once approved, the market for them will be very small. "Interventional MR has not grown a lot within the last ten years and, given the practical problems, you do wonder whether it is ever really going to take off," Keevil warns.

Spanner in the works

    Even if interventional MRI never reaches its true potential, open systems still greatly improve the patient experience and offer examinations impossible by any other means. Not surprisingly then, the number of open systems in clinical use is steadily increasing. But what can we expect in the future?

    Developments in the MRI field are driven both by the needs of the end-users and by advances in science and materials, says Blasche from Siemens. "We take care to understand the needs of our customers in different institutions, different countries, and with different healthcare systems," he says. "At the same time, we closely watch new developments and learn from experience. The best solutions are created when all these factors match perfectly."

    "We see a trend towards higher magnetic field strength," continues Blasche. "Twenty years ago, most routine scanners were sold at 1 tesla (T). Ten years ago, 1.5T became the clinical standard and is still approximately two-thirds of the world market, but the share of 3T systems has increased to approximately 20 per cent over the last few years."

    High magnetic field strengths are generally desirable in MRI because the higher the field, the higher the image resolution. Superconducting magnets produce the highest fields, yet lower cost electromagnets (as used by FONAR) and permanent magnets (the base of Esaote's scanners) can produce enough resolution for many studies. According to Esaote's Strategic Marketing Department, optimising all their scanners' components allows good image quality for bone, muscles and tendons in joints at the relatively low fields they use (0.25T for their G-scan for example). They see musculoskeletal scans being increasingly performed in dedicated systems.

    "We believe it is a waste of healthcare resources to use a 3T system for a routine knee examination," they say. FONAR also cite cost-effectiveness, along with high performance and a desire to "provide a set of unique imaging applications" as main R&D drivers.

    The future development - and use - of MRI scanners could, however, be thrown into jeopardy by the 2004 European Commission (EC) directive restricting occupational exposure to electromagnetic fields (Directive 2004/40/EC). This was due to come into effect in April 2008 and would, in its present form, limit the use of all MRI systems, including the open scanners. But as a result of further investigations showing workers routinely exceed the recommended limits for exposure with no evidence of side-effects and lobbying - in part by the UK's Institute of Physics - the implementation has been stalled until April 2012.

    Keevil, who was part of the lobbying process, says a working party is currently trying to re-word the directive in such a way that MRI will not be affected. If they don't succeed, we could be forced back to poorer quality imaging of soft tissues using harmful ionising radiation, which surely cannot be in anyone's interest.

How MRI works

    MRI scanners contain either permanent magnets or electromagnets (some of which are superconducting) typically able to produce a magnetic field of 1.5 tesla, which is 30,000 times greater than the Earth's magnetic field. The human body is almost 65 per cent water, and MRI images are obtained from the proton within each hydrogen atom in this water.

    Each of these protons spins about an imaginary axis like a spinning top, which makes the proton magnetic. The proton spins points in random directions until a body is placed in a scanner. Under the influence of the high magnetic field created by the scanner magnet, the proton spins align either parallel or anti-parallel to the field. Slightly more protons position themselves parallel to the field, creating a net magnetisation.

    A radio frequency pulse (a time-varying magnetic field) is directed at the area of the body that is to be studied. This changes the magnetisation of the protons in that region. Once this pulse is switched off, the protons relax into the state they were in before it was turned on.

    A conducting coil works as an antenna and detects - via electromagnetic induction - the small changes in magnetic field that the relaxation produces. As the type of tissue surrounding a proton influences its behaviour after the radio frequency pulse, computer software can analyse the detected signals and build up a detailed image of the body that shows different types of tissue. Graphical processors, originally developed by the computer gaming industry, are now used by some MRI systems to reconstruct and display images quickly.

© IET. Reproduced with permission.