Precisely targeted cancer treatment for East Netherlands
2 November 2006
Enschede, Netherlands. The Medische Spectrum Twente
(MST)hospital in Enschede, east Netherlands has installed the country's
first On-Board Imager (OBI) device for image-guided radiotherapy. The
hospital has begun clinical treatments using the new device, which enables
doctors to adjust the patient’s position at the time of treatment and ensure
the tumour is more precisely targeted.
MST is one of the Netherlands’
primary non-academic radiotherapy centres and the largest in the eastern
region of the country. Located a few miles from the German border, the
hospital treats patients from western Germany as well as the Twente region
of Holland. The centre is equipped with four Varian linear accelerators.
Dr Peter Helle, head of radiation oncology at MST Enschede, says the OBI
device has enabled his team to reduce treatment margins to within 2mm-3mm
accuracy, lower than the previous 5mm margins. “This will make a real
difference in our ability to focus higher dose on the tumour and avoid
damaging healthy surrounding tissue,” he says.
Doctors at MST Enschede
also plan to start a stereotactic radiosurgery program using the OBI device
on a Clinac iX linear accelerator, the treatment machine. “When you are
giving stereotactic treatments with doses of 60 Gray in three sessions or
18-21 Gray in one session — for small brain tumours for example — you
obviously need to be extremely accurate and the On-Board Imager will give us
that degree of precision,” adds Dr Helle.
Varian’s On-Board Imager makes
it possible for clinicians to image and treat on a single machine that
rotates around the patient to take X-ray images and deliver treatments from
virtually any angle. Mounted on the medical linear accelerator, the OBI
device produces high-resolution images of the tumour and tracks changes in
tumour shape, size or position over a multi-week course of treatment. It
also enables clinicians to track and adjust for tumour motion caused by the
patient’s breathing during treatment sessions.
The OBI device enables radiographic, fluoroscopic and 3D Conebeam CT
images to be swiftly acquired at the time of treatment. Any adjustments to
the patient’s position can be carried out by a radiography nurse entirely
from outside the treatment room.
Prior to the advent of image-guided
radiotherapy (IGRT), radiation oncologists had to contend with variations in
patient positioning and with respiratory motion by treating a relatively
large margin of healthy tissue around the tumour. IGRT enables doctors to
minimize the volume of healthy tissue exposed to the treatment beam.
Potentially, image data from IGRT tools like the OBI device will be used to
note changes in tumour size and shape over a course of treatment, and make
real-time adaptations to the treatment plan.
Max Takkenberg, Varian’s
Netherlands country manager, says, “This leading cancer centre has
demonstrated that it wants to offer its patients the most advanced,
highly-targeted radiotherapy for combating cancer. Varian’s fully automated
imaging and patient positioning system makes it possible for busy centres
such as MST Enschede to offer the most advanced image-guided treatments
within the standard 10-15 minute treatment period that is available for
patients. Automation is crucial because technology advances in this area
must not place an additional burden on staff and push up patient waiting