The Netherlands Cancer Institute has become the first in
Europe to administer radiation therapy to a cancer patient using a
3D MRI video. Doctors and researchers at the Amsterdam
comprehensive cancer center have developed software that they can
use to make a video of a tumour as it moves - due to the patient's
breathing for example. This will allow them to irradiate patients
even more accurately in the future so that healthy cells will
suffer less damage.
In the Netherlands, around 60,000 people every year
require radiation therapy for cancer. The radiation kills the
cancer cells, but it also damages healthy cells that are located
near the treatment site. This means that radiotherapists are always
looking for the right balance between a dose of radiation that is
high enough to destroy the cancer cells, but low enough to minimize
the damage to the healthy tissues and therefore side
In order to target the radiation as accurately as
possible, the radiation machine needs to be given information about
exactly where the tumour is located. Doctors use scans for this
purpose. However, the exact location of a tumour is difficult to
pinpoint with a single scan, because tumours can move due to the
patient's respiration, for example. The Netherlands Cancer
Institute's team has now devised a way to make a 3D MRI video which
shows the movement of the tumour in three dimensions (3D). Last
week, they became the first in Europe to administer radiation
therapy to a cancer patient using this kind of 3D video. The
patient was treated for a liver metastasis.
Since last year, doctors at the Netherlands Cancer
Institute have been treating patients using a new type of radiation
machine that incorporates an MRI scanner: the MR-Linac. Until now,
though, it had not been possible to take account of the movement of
the tumour and administer the treatment using a 3D MRI
This is an example of a 3D MRI video. That is, a flat
version of one. Doctors can explore the depth of this video by
scrolling through it from front to back and vice versa.
Doctors have been making videos using CT scanners built
into radiation therapy machines for some time already. However, CT
scans do not reveal (tumours in) soft tissues very well. For
patients with liver cancer, for instance, doctors therefore have to
insert small rods to use as visible markers. These markers enable
them to see which area to target with radiation therapy.
'The 3D MRI video means that we don't need markers
anymore,' explains radiotherapist Edwin Jansen, who treated the
first patient. This is because the
MRI scan can reveal the location of the metastasis
within the liver. 'That's good news because inserting the markers
can be a nasty procedure for patients. It can be painful and they
can suffer from infections or bleeding.'
Another important advantage is that the 3D MRI video
enables doctors to see the tumour as it moves, rather than just the
markers. They can see exactly which position the tumour is in as
the patient breathes. 'This way, we can see even better where we
need to focus the radiation,' explains Jansen. 'We hope this will
enable us to irradiate even more accurately than we already do.
That will reduce the chance of side effects and it may also enable
us to increase the radiation dose if necessary.'
How do you make a 3D MRI
Making a 3D MRI video involves quite a
bit more work than making a video on your mobile phone. The MRI
scanner makes 750 2D scans of the tumour over a period of 5
minutes. Using the new software developed at the Netherlands Cancer
Institute, a computer can then merge all the scans into a 3D video
that shows the movement of the tumour as the patient breathes.
Tessa van de Lindt spent four years of
PhD research on developing this new technique.
Benefit for patients
The first patient to be treated using a 3D MRI video is
participating in a clinical trial that will show whether it is
technically feasible to treat all patients with limited liver
metastases using this new method from now on. Radiotherapists call
these video's 4D MRI's. Marlies Nowee, radiotherapist and leading
the research project, explains: 'We are treating patients using
this new radiotherapy technique for the first time in this trial.
If everything goes well in the first group of patients, we may
offer the treatment to more patients. We won't need to insert
markers any more, that's already a real benefit for patients.'
The doctors at the Netherlands Cancer Institute are
currently only using this new technique to treat patients with
limited liver metastases. Later, they hope to extend the treatment
to tumours in other organs that move during radiation therapy.
Cancer patients with extensive metastases usually receive systemic
therapy such as chemotherapy or immunotherapy. But if there are
only a limited number of metastases, localised treatment through
surgery or radiation therapy may be an option. Doctors decide which
treatment is the most suitable for a patient at a multidisciplinary
meeting, where they take into account more than just the number of
- The Netherlands Cancer
Institute has become the first in Europe to administer radiation
therapy to a cancer patient using a 3D MRI video. This technique
reduces the invasiveness of the required treatment, and it enables
doctors to see the movement of a tumour just before radiation
therapy is administered so that they can take the movement into
account while planning the treatment.
- The new technique is currently
only being used as part of a trial involving a small group of
patients with limited liver metastases. The trial will reveal
whether the technique is technically feasible.
- For more information about this
treatment, please contact: +31 (0)20 512 9111 (ask for the Patient