APPENDIX 3
Memorandum from Dr Alan M Calverd
INTRODUCTION
I write in my personal capacity, but with the
particular experience knowledge and interest acquired in my capacity
as the EU Authorised Representative for the FONAR Corporation,
Melville, Long Island, USA, and as Technical Manager of one of
its customer Companies operating clinical MRI systems in the UK.
In view of the short time available to me for
comment, these notes have been prepared in good faith but have
not been cleared by FONAR or any other Company or group with which
I am associated. They represent my personal opinion only.
THE FUTURE
OF INTERVENTIONAL
RADIOLOGY
I have been privileged to work in the past with
Prof Louis Kreel and a number of other innovators in the field
of realtime x-ray-guided surgery and angioplasty. The benefits
of these minimally intrusive, low-risk and low-cost procedures
compared with open surgery are manifest, and they have taken their
place in the routine armamentarium of most hospitals.
The next logical stage in the development of
such procedures is clearly to explore the benefits of MRI, which
permits better visualisation of soft tissues without the use of
toxic contrast agents, and can be used to characterise the chemical
status of a region infused with a cytotoxin, or the physical state
of a polymerising resin. In principle this allows us to, say,
precisely ablate a tumour with negligible damage to surrounding
tissues, or to effect exquisitely controlled repairs of fractured
or collapsed bone.
BRITAIN AT
THE LEADING
EDGE—FOR
NOW
The key to image-guided interventions is the
ability of the surgical team to access the patient close to the
surgical site, and to carry out anaesthesia and intraoperative
monitoring safely and efficiently. To this end, FONAR have developed
the OR360 "operating theatre in a magnet", currently
the only MRI system that allows unrestricted access to the patient,
and among the most powerful (thus fastest and most precise—ie
safest) open MRI systems on the market.
The first commercial OR360 in the world is now
nearing completion at the Oxford Nuffield Orthopaedic Centre,
where it will be used, with considerable support from the manufacturers,
to explore its potential for high-throughput routine imaging and
in truly "hands on" interventional procedures. ONOC
was particularly favoured for this work on account of its established
reputation in orthopaedic radiology and the unique enthusiasm
and expertise of its clinical research and development teams.
Development of intraoperative imaging in this,
the likely precursor of a new family of MRI equipment, clearly
encourages operators to work close to and even inside the primary
magnetic field and gradient fields, which are confined between
the pole pieces above and below the patient. The optimum positioning
of, say, a surgeon's hand, is determined by the patient's anatomy:
there is no substitute for tactile sensation in medicine, and
the OR360 uniquely permits the combination of direct contact through
a surgical tool, with the ability to visualise anatomy and chemistry
deep inside the patient.
The proposed EU restriction on operator exposure
to time-varying gradient fields will severely restrict the scope
of work that can be legally done in such machines, and will place
severe limits on the development of both the equipment and its
applications. I fear that clinical research in interventional
MRI will be effectively curtailed in the UK, and British patients
will be denied the benefits of those techniques that have been
developed. If the future of close-contact interventional MRI in
the UK is is doubt, there seems little point in putting the machine
into use at all, and several million pounds of NHS capital expenditure
may as well be written off before it is switched on.
CRITIQUE OF
THE EU DIRECTIVE
The "precautionary principle" is,
reductio ad absurdam, the antithesis of any form of progress
or innovation. It is an anomalous basis for legislation in a rational
society that generally prefers evidence to superstition or ignorance,
and it sits ill with the British courts' insistence on proof of
actual harm in determining real cases. Until the 20th century,
no human had been subjected to an acceleration in excess of 1g,
or travelled faster than a horse. Adoption of the precautionary
principle in, say, 1900, would have prevented the development
of the aeroplane or the motor car.
The supposed basis of the Directive's exposure
limits to time-varying magnetic fields is an arbitrary multiplier
applied to a reported threshold for some subtle, transient physiological
effects. If the same arithmetic were applied to such transient
effects as hearing or vision it would be illegal to speak or switch
on a light.
A familiar transient physiological effect, such
as vision, hearing or the sensation of touch or temperature, is
not a health hazard. A novel transient physiological effect cannot
be considered to be a health hazard unless it has been shown to
be detrimental to health, or some plausible mechanism of potential
harm can be adduced from our present knowledge of physiology.
Simply because homo sapiens has not been exposed to time-varying
magnetic fields in the historical past is no reason to suppose
that they are a danger to health now, and there is no evidence
from the last 30 years of magnetic resonance imaging that gradient
fields have harmed any operator to date.
It is not clear what authority a free trade
organisation like the European Econmomic Community has to prevent
the development and application of interventional MRI in the UK.
January 2006
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