Brain Cancer Procedures:
A primary brain tumor is a group
(mass) of abnormal cells that start in
PHOTODYNAMIC THERAPY FOR
Doctors usually treat brain tumors with
surgery and radiotherapy when they
are first diagnosed.
Photodynamic therapy (PDT) is a new
treatment that is still being tested in
clinical trials for a few different
cancers, including brain tumors. So
far, PDT trials for brain tumors have
recruited patients whose cancer had
come back after treatment. This trial is
looking at the use of PDT alongside
surgery and radiotherapy as part of
your first lot of treatment.
The aim of this trial is to see if it is
better overall to have PDT alongside
surgery and radiotherapy to begin
with, or to wait and have PDT if the
cancer comes back.
When you have PDT you have a drug
called Photofrin. This is a
photosensitizer. In other words, it
makes you more sensitive to light.
Photofrin mainly goes into your brain
tumour cells. Very little goes into
normal brain cells.
About 48 hours after your Photofrin
the doctors use a carefully placed light
fibre and keyhole surgery to shine a
laser directly onto your brain tumor
cells. When they shine the laser onto
the cancer cells that have taken in the
Photofrin, the cells die.
If the scans show that the PDT has
worked well, but your cancer starts to
grow again in the future, you may be
able to have PDT again.
GAMMAKNIFE VERSUS CYBERKNIFE
FOR BRAIN SURGERY
Neurosurgeons will tell you that
immobilizing the target – the patient’s
head – is the first step in performing
any type of brain surgery. The most
widely used neurosurgical head frame
– called a stereotactic frame – is
manufactured by Elekta, and it’s the
same stereotactic frame used with
Gamma Knife surgery.
CyberKnife claims that no head frame
is required for stereotactic
radiosurgery. Instead they use a
claustrophobic mask that is pressed
against the patient’s face for hours.
And despite the constraint, their head
can still move.
With Gamma Knife radiosurgery, a
head frame is attached with temporary
placement pins and the patient has a
single MRI – the preferred method of
imaging the brain. There are no X-rays.
Because CyberKnife and other linac
treatments recommend use of a face
mask instead of a head frame, X-rays
of the brain must be taken every two
minutes during treatment to ensure the
target hasn’t moved.These added X-
rays increase radiation exposure to the
patient and lengthens treatment time.