Examination of Witnesses (Questions 805-819)
DR STEPHEN
KEEVIL, PROFESSOR
COLIN BLAKEMORE
AND PROFESSOR
RAY DOLAN
17 MAY 2006
Q805 Chairman: May I welcome
to this session of the Science and Technology Select Committee
our first distinguished panel, Dr Stephen Keevil, Professor Colin
Blakemore, and Professor Ray Dolan. Welcome. This is our third
case study which is looking at the whole issue of scientific advice
to government. We chose specifically the issue of MRI scanners
because of the European Directive. We wanted to effect a policy
trail to determine where that Directive originated and how it
got to the place it is now, and also to look at some of the controversy
surrounding the implementation of the Directive and how it will
affect what has been a massive investment by the UK Government
in terms of MRI scanners in our hospitals. That is the purpose
of this morning's session. We are aiming to finish this first
session by 25 past 10. I wonder if it would be possible, Dr Keevil,
to ask you to chair your panel, in case there is huge argument
that breaks out, in which case you can deal with your unruly colleagues
on either side.
Dr Keevil: I would
be very happy to do that.
Q806 Chairman: Professor
Blakemore is known to be difficult! This is the second evidence
session. Last week we were in Europe meeting the Commission and
the Commission officials told us that the new Directive would
have absolutely no impact on treatment using current practices,
and the concerns of the medical community and the manufacturers
were dismissed by the Commission as "views". What is
your view?
Dr Keevil: I have had the opportunity
over the last 24 hours to look at the transcript from that evidence
session and to share it with colleagues in the MR community. I
think the concerted opinion of all those individuals was one of
astonishment at some of the comments that were made in that session.
When I visited Brussels in March with colleagues from seven other
European countries to express our concerns about this Directive,
we sent ahead of us a detailed summary of the areas where the
Directive is going to impact on MRI, both in current clinical
practice and in emerging applications and in research, which very
clearly spelt out our concerns. Really, in that context, it is
amazing that those individuals could say that there is no impact.
There are a number of misconceptions and factual inaccuracies
in the evidence that was given. I have already, through the clerk,
asked for the opportunity to submit a further written submission
which deals with those points in detail.
Q807 Chairman: Does that
surprise you, that the Commissioners who were responsible for
drawing up this Directive, who have been responsible for it from
start to finish, have made such basic errors?
Dr Keevil: One thing that astonished
me was to discover from that evidence that this is a process that
has been going on since 1992. I am one of probably half a dozen
to ten people in the UK MR community who are most engaged with
this issue and I was certainly unaware that it went back that
far. I think that speaks to the lack of consultation with the
community which has gone on. From that evidence it was clear that
really they have listened to one source of information: the ICNIRP
Guidelines. There was a statement there to the effect: We spoke
to ICNIRP and they said there would be no impact on MR, so that
is it—you know, putting ICNIRP up to be the experts on MR
practice, machine design and use, which I do not think ICNIRP
would pretend to be. In that sense it surprised me. I have wondered
throughout this process how it is that the guidelines like those
that ICNIRP have and the NRPB have, which are very cautious—if
you read the guidelines they say that this is a cautious interpretation
of limited scientific data—ever got to be turned into concrete
exposure limits. I think now, having read the transcript of last
week's session, I can understand that, having a bit more insight
into the thought processes of the people who were behind those
decisions.
Q808 Chairman: Could I
pin you down on the issue of what we would call diagnostic applications
and ask you to give me a brief answer—and the same applies
to the rest of the panel: Do you feel that this Directive will
have real impact in terms of diagnostic applications if in fact
it is implemented in its current form?
Dr Keevil: Yes. It is true to
say that probably the vast majority of clinical diagnostic MR
imaging would not be directly affected. It depends to some extent
on how the problem of moving through the static field gets interpreted.
That is slightly open to different views and interpretations.
But there are certainly important areas of diagnostic imaging,
important groups who need to undergo MRI, which it would be much
more difficult to image in a post-Directive regime. There are
whole new areas, like interventional MR, which would be effectively
blocked by this. I know you were told that interventional MR systems
are all very low-field machines that pose no problem, and a figure
of 0.4T was mentioned—although, given that there is not
a static field limit in the Directive, it is not immediately obvious
why the static field value is so important—but actually
it is not true. In my hospital we have two 1.5T interventional
MR systems, and I know that in Professor Dolan's institution another
machine is being put in at the moment, so it simply is not true.
Q809 Bob Spink: My understanding
is that at the moment, for instance for neurosurgery, the images
that you get from 0.4T or even 0.5T machines are quite poor, and
that is holding back the development of this. In order to get
a better image so that this procedure can be used much more—as
it is, for instance, in Australia—you would need more powerful
machines to give better images, and that would give much better
outcomes for brain surgery.
Dr Keevil: Yes, I think the gold
standard now for neuro-imaging is 3T. There are hospitals in the
world that are now starting to use 3T for neuro-intervention as
well. This is more Professor Dolan's area.
Professor Dolan: The critical
point here is that, the higher the field strength, as a general
rule the better the spatial resolution is and the ability to see
smaller areas of tissue, down to sub-millimetres. That becomes
very important in certain areas, for example when it comes to
doing neurosurgery, where one has to be very careful at the level
at which one excises a piece of brain: one wants to excise what
is diseased but preserve what is carrying out important cognitive
functions. In the field of neurosurgery, critical developments
are going to occur, in the sense that you will be able to inform
the patient: "We will be able to do this type of intervention
and this is going to be the likely outcome." In the past,
because of a lot of neurosurgery was done blind, there were often
disastrous outcomes, in terms of people being left, say, with
language impairments, or other critical cognitive impairments.
For the future in neurosurgery, the ability to inform a patient
about what is the likely outcome, so that they can give appropriate
informed consent, will depend also upon the ability of the surgeon
to know that they can excise a discreet area of brain and nothing
else, and the developments in high-field MRI are going to be critical
in this respect.
Q810 Dr Harris: The Commission
officials, as you saw, were very specific that what has just been
said—that this would interfere with diagnostic testing—is
an opinion; it is not evidence. They in fact, in contrast, as
we will go on to discuss, talked about how the effects on health,
backing-up these guidelines, will have been published in peer
review journals. Can you help us by identifying that the opinion
you give, that these action limits and maximum limits would impact
on diagnostic and therapeutic interventional procedures, are published
somewhere in the form of evidence, in peer-reviewed scientific
journals, with a conclusion to pass muster which states: "These
limits would interfere"?
Dr Keevil: The best way of starting
that is by looking at the example of my own institution, where
we are doing MR-guided cardiac catheterisation on children who
traditionally would have had those procedures under X-ray guidance
(which involves a dose of ionising radiation, et cetera). We published
the first results of that in the Lancet in 2003 showing
the clinical efficacy. We were not looking there at the occupational
exposure on the staff members, but I have done some measurements
looking at where the interventionist stands who is carrying out
those procedures, right at the bore of the magnet to insert the
catheter, and we are over the relevant action value in the Directive
(which is in the hundreds to thousands of hertz range for the
switched field gradients that are used as part of the imaging
process). We are over that action value by a factor of about 40.
Q811 Dr Harris: But that
is not published.
Dr Keevil: It is not published.
Q812 Dr Harris: That is
just your personal statement.
Dr Keevil: Indeed. However, I
know that colleagues at the Royal Marsden Hospital have done some
more extensive measurements around their two or three 1.5T scanners,
looking both at static field and at gradient field characteristics,
and that has been submitted as a paper for review. So it is going
through the process. It is not yet published.
Q813 Chairman: Could I
come to you, Professor Blakemore. In terms of the impact on research,
do you feel that this Directive, if implemented in its current
form, will have a significant impact on the very research which
Professor Dolan and Dr Stephen Keevil have just been talking about?
Professor Blakemore: There is
no doubt that it will have more immediate impact on research than
on clinical practice. I cannot comment fully on the impact on
clinical practice, but, you know, research has a way of turning
into practice. We have seen trends in the way in which scanning
has been used in the last few years for clinical treatment which
have involved more interaction with the person being scanned,
with clinical staff or other staff in the same room moving around
the scanner, necessarily, as part of the intervention. It is that
sort of situation where there seems to be most focus of concern.
That of course is routine in much research use of MRI, where the
research often has to engage with a volunteer or a patient while
in the scanner, carrying out some particular test with them. If
one considers what the likely impact will be in that area, I should
like to point out that, within the next few months, MRC and the
British Heart Foundation will be funding the installation of a
number (probably six to eight) 3T whole-body scans around the
country for clinical research—that is research aimed at
moving into clinical practice. These are high-intensity machines,
the choice driven by the relationship between resolution and field
strength which has already been described by Professor Dolan.
There is no doubt that the Directive, if implemented in its present
form, would have an impact on such research in this country and
indeed around Europe.
Q814 Chairman What steps
did the MRC take to establish the potential impact on research
of the Directive? Were you involved? Whom did you consult? What
representations did you make to the Commission? Because, clearly,
you must have seen this coming.
Professor Blakemore: Frankly,
I personally—and I think this applies to other MRC staff—had
no warning of this at all until about six months ago or thereabouts
when I was approached by the HSE and invited to attend a workshop.
In fact, Professors Derek Hill and Jo Hajnal went as representatives
of the MRC to that workshop. We were not involved in the discussions
with the Commission that led to the draft Directive. Perhaps it
is not surprising that the Commission was not fully aware of the
impact of the Directive on MRI.
Q815 Chairman: But the
MRI community from an early point were aware. Was there no discussion
with MRC about that?
Professor Blakemore: Not that
I was aware of until about six months ago.
Q816 Dr Iddon: Could we
look at the health effects. You have mentioned a gold standard,
Dr Keevil, of 3T. Are there any adverse health effects at levels
like that? If we are likely to exceed 3T in the future because
of the improved imaging, do you anticipate that there might be
significant health effects later?
Dr Keevil: For one thing, this
is not an issue that is just about static fields. There is the
static field, there is the switch gradient, there is the RF as
well. In terms of the impact of the Directive, our concerns at
the moment are mostly about the gradient field issue rather than
the static field, because at the moment there is not a static
field limit in the Directive. Because this is a Directive that
covers such a broad frequency range, it is important to consider
those frequency ranges separately because their impacts are different.
The physics is different; the biology is different. I think there
was a degree of confusion in the evidence you took last week between
different frequency ranges. Statements were made that are true
in one range but were applied incorrectly to another, so it is
important to separate those out. Speaking specifically of the
static fields, to respond to your particular question, the effect
that people most frequently report in terms of static field, on
moving through a higher static field, is a feeling of dizziness.
That is quite well attested. People talk about that at 2T upwards,
and certainly if you are working at the highest current field
strength, whole body system, 7T/8T, then that is a concern and
people need to have working practices in place to minimise the
impact of that on their work and on their safety, and of course
they do. We are a well informed community, we are a very safety-conscious
community, and so people do have those procedures in place. There
was some comment again last week about the possible mechanism
of that, about it being due to the movement of calcium ions in
neurons. There is no evidence for that at all—we think it
is due to an interaction with the inner ear, in fact—so
that is another falsehood in that evidence. Nobody is suggesting,
whether we are talking about static field or any of the other
frequency ranges, that there are no effects and that we can sit
there complacently and have no limits at all. We know there are
effects. For example, in the gradient frequency range, if you
go to high enough amplitudes, you get peripheral nerve stimulation,
where people's muscles start to twitch because they are being
stimulated by the currents that are induced. There are real effects
and we need to be aware of those and indeed have guidelines and
if necessary regulations in place to prevent those from occurring
either to staff or to patients.
Q817 Dr Iddon: I think
you are saying that most of the health effects are reversible
when the patient or the operator is taken out of the room.
Dr Keevil: Yes. I am not aware
of any irreversible effects.
Q818 Dr Iddon: The EU
Commission has based its Directive on the 1998 ICNIRP guidelines.
You have been critical of that procedure. I think you have been
quoted as saying that the guidelines were based on "a cautious
interpretation of sparse scientific evidence".
Dr Keevil: Indeed.
Q819 Dr Iddon: When the
Committee were in Brussels last week, obviously Members put that
point, and officials in Brussels vigorously defended their position.
Perhaps you would like to make your position clear this morning.
Dr Keevil: Yes. Without wishing
to put words into their mouths, the officials were saying that
this is the guidance that has come from ICNIRP and they are the
experts and so we accept that guidance. To some extent, I can
understand that position, but you have to look at what the ICNIRP
guidance is saying. Because we are in a grey area, where really
there are not proven adverse health effects at these levels of
these frequencies, the statement in the Directive that it is about
preventing known adverse health effects that occur acutely is
not true. There is not the evidence for that.
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