March 2012 - Institute of Physics and Engineering in Medicine

SCOPE | MEETING REPORTS
ADVANCED CLINICAL MR IN ONCOLOGY:
TECHNIQUES FOR TREATMENT PLANNING
SARAH BACON AND DANIEL WILSON St James’s Institute of Oncology, Leeds
LEEDS METROPOLITAN UNIVERSITY 19th July 2011
THIS MEETING, ORGANISED BY the Magnetic
Resonance Special Interest Group, aimed to provide
medical physicists with an overview of the latest
research and developments involving MRI for
treatment planning and response assessment in
oncology applications. The meeting attracted just over
70 attendees.
OPENING SESSION
The meeting was opened with a quick introduction by
Daniel Wilson (Leeds Teaching Hospitals), who also
chaired the first session. John Brunt (Clatterbridge
Centre for Oncology, Wirral) was invited to give an
overview of the use of MR in radiotherapy treatment
planning (RTP) covering the benefits that MR has over
CT as well as some of the problems and issues that
arise. MR has the potential to be used in many areas of
RTP and is currently primarily used by co-registering
MR images with CT planning images. The first of the
proffered papers of that session was by Keith
Langmack (Nottingham University Hospitals) who
followed on from the previous talk by showing
various solutions that his centre have come up with to
facilitate the use of MR in RTP. These include flat
couch tops, scanning patients in the treatment position
and the use of cardiac coils for head and neck imaging
of patients in their treatment shells. Sophie Riches
(Royal Marsden Hospital, London) gave the next
paper on functional MR (fMRI) methods for RTP in
the prostate. The functional MR methods include
diffusion-weighted (DW) MRI, dynamic contrast
enhanced (DCE) MRI and 3D-MR spectroscopic
imaging (MRSI). These methods can work well in
identifying prostate cancer but there are some issues
associated with the use of hormone therapy in
prostate cancer patients that can cause degradation of
the functional MR results and shrinkage of the
prostate.
THE IMPORTANCE OF SETUP
Scott Hanvey (Beatson West of Scotland Cancer
Centre, Glasgow) presented work on the importance
of setting up prostate patients in the treatment
position for a planning MRI scan. They found that
registering CT with MRI significantly reduced the
target volume and the registration was of higher
quality for patients who were scanned in the
treatment position. The last talk of the session was
given by Joshua Mason (Leeds Teaching Hospitals),
who presented results of a feasibility study on using
MRI to guide prostate high dose rate brachytherapy
boost. He found that it was possible to identify boost
volumes using T2-weighted (T2W), DW and DCE
MRI, although there are issues associated with
registration and the effects of hormone therapy.
The second session of the day, after a coffee break,
was chaired by Gary Liney (Queen’s Centre for
Oncology, Castle Hill Hospital, Hull) and started with
an invited talk by Laura Mancini (University College
London Institute of Neurology) on using fMRI for
surgical planning of brain tumours. Particular
applications include avoiding critical functional
structures within the brain which are identified using
fMRI. This technique is based on the change in
oxygenation of the blood in activated brain areas.
Geoff Charles-Edwards and Marium Naeem (Guy’s
and St Thomas’ NHS Foundation Trust, London)
presented Robert Johnstone’s talk on commissioning
MRI for high dose rate brachytherapy planning. They
covered multiple aspects of this process including
checking that the applicator did not result in excessive
heating during the MRI scan, choice of T2W MRI
protocol and measurement of MRI distortions due to
the applicator.
David Manton (Yorkshire Cancer Research Centre
for MRI Investigations, Hull) presented work on
improving metabolite ratio mapping in MRSI to
improve its use in RTP. Different methods for
improving the accuracy of the metabolite ratios were
presented. Jill McKenna (Northern Centre for Cancer
Care, Newcastle upon Tyne) described work
performed to streamline the treatment of patients who
require radiotherapy for the treatment of metastatic
spinal cord compression. The initial work looks
promising if a dedicated diagnostic and radiotherapy
planning MR study can be performed. This may
remove the need for an additional planning CT in
those patients. Before the lunch break, Ruhenna
Mendes (University College, London) gave the final
paper of the session on the role of co-registration in
target definition in head and neck cancers. MRI offers
some distinct advantages over CT for RTP, including
superior tumour delineation and better identification
of organs at risk. MRI must currently be co-registered
with CT and this requires particular attention to be
paid to identical patient setup for good rigid body
image registration results. Improvements in non-rigid
body image registration may lead to larger setup
variations being tolerated.
AFTERNOON SESSION
The first session of the afternoon was chaired by
David Buckley (University of Leeds) and the talks had
more emphasis on treatment response. Ferdia
Gallagher (University of Cambridge) gave an invited
talk on monitoring response with MRI. He focussed on
current techniques such as DW and DCE-MRI and
then gave an overview of work involving
hyperpolarised 13 C which has several promising
applications in the field of response assessment. The
40 | MARCH 2012 | SCOPE