APPENDIX 62
Memorandum submitted by Mr Graham Lewington,
Business Development Manager, Mobile PET Systems (UK) Ltd
1. INTRODUCTION
1.1 The London PET Centre Ltd (LPC) and
Mobile PET Systems (UK) Ltd (MPSUK) are wholly owned subsidiaries
of Mobile PET Systems Inc (MPS) San Diego, California, USA.
1.2 LPC and MPSUK are the first privately
funded Dedicated, Full Ring, Positron Emission Tomography (PET)
providers in the United Kingdom.
1.3 Prior to his appointment at LPC and
MPSUK in September 1999, Graham Lewington had spent 12 years involved
in PET research centres at both the Medical Research Council's
Cyclotron Unit, Hammersmith Hospital, Du Cane Road, London and
the Wellcome Department of Cognitive Neurology, Institute of Neurology,
University of London, Queen Square, London.
2. SUMMARY
2.1 This memorandum seeks to identify and
outline the uses and needs for PET in the early detection, effective
staging (spread) and the recurrence of tumours for cancer patients
in the UK.
2.2 PET is an advanced nuclear medicine
technique that is both very sensitive and very specific. Its availability
in the UK is presently limited, largely to the South East of England.
2.3 Recent changes in operational procedures
have led to the ability to establish stand alone clinical PET
centres which are able to offer this modality to patients on a
more local level, without the need for the historically associated
large capital expenditure and investment in the infrastructure
that were a prerequisite of such centres in the past.
2.4 PET represents a cost-effective addition
to patient management that often obviates the need for other diagnostic
procedures, including surgery.
3. WHAT IS
PET?
3.1 PET is a metabolic imaging procedure
unlike Computerised Tomography (CT) and Magnetic Resonance Imaging
(MRI), which are both anatomical scanning modalities.
3.2 PET shows metabolic activity in human
cells and can detect tumour activity at an earlier stage than
other modalities. This is particularly useful when looking at
the extent of spread of disease throughout the body. One whole
body scan can readily identify the extent of metastases and also
locate, more accurately, the primary site of disease.
3.3 For many years PET has been a research
tool, used mainly for studying both normal and dysfunctional systems
in both humans and animals. A great deal of knowledge has been
gained, primarily concerning the function of the human brain,
assessment of the function of the heart and about the nature and
extent of the disease in cancer.
3.4 Research continues in a growing number
of centres internationally, as PET represents the "Gold Standard"
imaging technique for the study of physiological and biological
processes in vivo, but in the last two years PET's use
as a first line, clinical, diagnostic tool has come of age.
3.5 Findings from research, using PET for
oncology, have provided a compelling argument for its routine
use in cancer centres.
3.6 PET scanners are able to utilise the
unique properties of positron emitting radionuclides, which give
off two anti-parallel 511 keV photons as a result of the annihilation
of a positron and a free electron (positrons, being of the same
mass, but opposite "charge" to an electron).
3.7 Positrons are emitted as a part of the
decay process of positron emitting radionuclides.
3.8 Assuming the two 511 keV photons are
detected within a short time frame (effectively simultaneously)
by the detectors within the scanner, then an annihilation event
can be said to have occurred at some point along the "line"
between the two detectors.
3.9 Modern dedicated, "full-ring"
PET scanners contain thousands of detecting crystals, which allow
for the detection of millions of these "events" during
the course of the scan.
3.10 The resultant images are able to demonstrate
effectively those areas in the body that are more metabolically
active than others, as a result of the higher uptake of the positron
emitting radionuclides.
3.11 This fact means that PET is generally
more sensitive than conventional nuclear medicine gamma cameras,
CT scanners or MRI scanners in some cancers.
3.12 Compared to CT scanning in lung cancer
PET has a sensitivity of 81 per cent compared to 52 per cent.
In colo-rectal cancer PET demonstrates a sensitivity of 95 per
cent as opposed to 68 per cent in CT.
3.13 PET is also highly specific. Lung cancer
may present as a solitary pulmonary nodule. The incidence of these
nodules is high, but few imaging criteria can reliably differentiate
benign from malignant nodules.
3.14 It is currently estimated that 50 to
60 per cent of solitary pulmonary nodules are benign, resulting
in a substantial number of patients being needlessly exposed to
peri- and post-operative complications.
3.15 Considerable experience is now available
concerning the diagnostic value of PET in solitary pulmonary nodules.
3.16 Use of PET for differentiation of solitary
pulmonary nodules could lead to significant savings in addition
to reducing the number of complications during management.
4. OPERATION
OF CLINICAL
PET SITES IN
THE UK
4.1 PET centres have historically required
a large infrastructure relying upon the close proximity of a cyclotron
for the supply of the necessary positron emitting radionuclides.
There was also a need for a radiochemistry laboratory and a large
team of qualified personnel to produce the tracers.
4.2 Within the last two years "stand
alone" PET scanning centres and mobile PET units have come
about. These scanners can operate as a result of using the longer-lived
positron emitting radionuclides, such as 18F labelled deoxyglucose
(FDG).
4.3 18F has a half-life of 110 minutes,
which enables its use at a distance from the cyclotron which produced
it.
4.4 Currently the most widely used clinical
PET tracer is FDG. FDG is a glucose analogue that can be used
to demonstrate the raised glycolysis within tumour cells. It is
non-specific, showing raised uptake in certain normal healthy
tissue such as the myocardium as well.
4.5 More specific PET tracers are currently
being developed for remote PET centres. In the past these tracers
have tended to be labelled with other, shorter-lived isotopes
such as 11C, with a half-life of 20 minutes. This short duration
effectively rules out use at a remote unit and requires the cyclotron
to be on the same site as the scanner.
5. ISOTOPE AVAILABILITY
5.1 A cyclotron is necessary for the production
of the majority of the isotopes essential for PET scanning.
5.2 Cyclotron facilities in the UK are generally
in the domain of a few university PET centres. These centres conduct
research and generally use their equipment for scientific reasons,
although increasingly they are making some longer-lived isotopes
available for clinical use.
5.3 There are commercial companies that
plan to develop more centres for manufacture of PET isotopes as
a commodity product.
5.4 Ultimately, a network of between 7 to
10 cyclotrons would be able to service the needs of all remote
and mobile scanner platforms in the UK, with sufficient 18F compounds
for their daily needs.
6. THE COST
EFFECTIVENESS OF
PET
6.1 Recent studies coordinated by the Institute
for Clinical PET ("ICP"), in the United States, have
shown that, despite the relatively high cost of the equipment,
PET is very cost-effective for a number of indications, due to
the amendment in patient management following PET studies.
6.2 Healthcare institutions in the United
States cite figures as high as 80 per cent for the change in patient
management following a PET study.
6.3 PET can effectively detect the source
of many of the most common cancers, often obviating the need for
other imaging techniques or diagnostic surgical procedures.
7. CURRENT CLINICAL
PET SITES IN
THE UK
7.1 Despite its proven efficacy, PET as
a clinical tool is not widely available to clinicians in the UK.
There are only five clinical dedicated, full ring PET centres
in the entire country.
7.2 These are concentrated in and around
London.
7.3 Whilst conducting market research throughout
the UK, MPSUK has identified a real need to expand the level of
availability of this system.
7.4 Currently any patients in regions outside
of London can only be offered PET diagnosis by travelling to one
of the centres in London. This can often mean a long wait (not
ideal where cancer is concerned) and a long journey to and from
London, which can be stressful as well as uncomfortable.
7.5 The patients' doctors are not always
happy to devolve their patients' management to a third party,
preferring to retain the management and services at a local level.
7.6 Those centres that currently offer PET
services report waiting times for a scan of between three to six
weeks. Despite the intentions of LPC to enable prompt and quick
access to this modality it would seem that, due to referral rates
at LPC, there will be a rapid growth to capacity and, if extrapolated
across the entire UK, it demonstrates the need to make this type
of imaging more widespread. This is particularly true as we are
involved with the management of cancer as delays in diagnosis
and detection can result in a poorer prognosis for the patient.
7.7 Ultimately there will be a need for
PET facilities at all regional cancer centres throughout the country.
8. MOBILE PET'S
CONTRIBUTION
8.1 PET scanners are now available in a
mobile configuration.
8.2 This will lead to improvement in access
to PET in those areas where provision is poor by:
8.2.1 Developing PET referrals in regions
that are likely to possess a static unit at some point in the
future, ie regional cancer centres, thus ensuring the success
of those centres when they become operational.
8.2.2 As well as supplying PET services to
hospital sites that need access to PET, but which could not justify
the long-term provision of a dedicated site.
8.3 Mobile PET is a risk-free means of gaining
access to the technology. It enables hospitals to use the facility
on a daily basis thus rendering large capital investments unnecessary.
8.4 Mobile PET also protects against technological
obsolescence, by ensuring that the latest "state of the art"
scanners will always be available.
9. CONCLUSION
9.1 Where available, PET already dramatically
alters diagnoses and, therefore, treatment regimes for a significant
number of cancer patients in the UK.
9.2 This could lead to improved prognosis;
less inappropriate surgery; shorter waiting lists and ultimately
a reduced cost burden to the healthcare services in the UK.
9.3 A raised level of awareness of both
PET and its predicted availability is necessary. This will require
education within the clinical community for the uses of PET. PET
is too often viewed as an expensive research tool with limited
availability.
9.4 If PET were more widely available, the
patient referral numbers would increase and patient management
would change to include PET at an early stage in the patient's
diagnostic evaluation.
9.5 The market for novel diagnostic imaging
techniques, using MRI as an example, went through a lengthy latency
period before it experienced explosive growth culminating in its
current universal acceptance. The limiting factors were largely
the same with PET: education within the medical community and
high equipment costs. The market for PET has experienced similar
latency issues but now appears poised for similar growth and acceptance
as MRI.
10. APPENDICES[33]
10.1 "Is It Possible To Practise Clinical
Oncology in the Year 2000 Without Dedicated PET Scanning Facilities?"
A review article by Dr P N Plowman MA MD FRCP
FRCR, Consultant Radiation Oncologist, St Bartholomew's Hospital,
The Royal London Hospital, Great Ormond Street Hospital for Sick
Children.
10.2 "The Power of Molecular Imaging—PET".
10.3 "Symposium on Positron Emission
Tomography".
Nuclear Medicine Communications ISSN 0143-3636—Published
by Lippincott Williams & Wilkins (Pamphlet not included as
non-availability at time of this submission).
33 Not printed. Back
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