Your consultant will discuss which treatment regime is best for
you at your clinic appointment and may go into some detail about
what to expect when you attend for your planning CT scan and
radiotherapy treatments. Depending on where on your body you are
having treatment, the 'planning' stages will vary.
See the tabs above for a general summary of each stage of your
radiotherapy treatment.
What we do
As we are one of the specialist centres in the South West we
provide a wide range of specialist treatments, including treatments
for paediatrics and adolescents; total body irradiation,
stereotactic ablative radiotherapy (SABR) and chemo-radiation. The
machines used to deliver these complex treatments are Elekta linear
accelerators. The following are some of the specialist treatment
techniques used:
IMRT
Intensity-modulated radiation therapy (IMRT) delivers an
advanced type of high-precision radiotherapy by shaping the
radiation beam to closely fit the treatment area and by modulating
or conforming the intensity of the radiation beam. This causes
different doses of radiation to be given across the tumour,
ensuring the best possible coverage of the treatment area. The
shape of the beam is achieved by using several thin fingers of lead
which move independently of each other called multileaf collimators
(MLC's) and are found within the head of the machine.
IGRT
Image Guided Radiotherapy (IGRT) is the use of advanced imaging
techniques to verify your position and anatomy before, during and
after your radiotherapy treatment. This ensures the treatment is
being accurately delivered to the treatment area. CBCT (cone beam
CT), KV (kilovoltage) imaging and ultrasound are used to take these
images while you are in the treatment position. The images
are reviewed by the radiographers who then apply movement
corrections, via the treatment couch, that account for twists and
tilts in the body, changes in body weight and organ motion so we
can accurately and safely deliver your treatment. Using IGRT
reduces the radiation dose to the healthy tissue therefore
minimising side effects.
VMAT
Volume Modulated Arc Therapy (VMAT) is a type of IMRT which
allows the high energy X-rays to be conformed to the shape of the
tumour whilst ensuring that the dose to your surrounding tissues
and organs is as small as possible by using MLCs. By using this
treatment technique, we can vary the intensity and shape of the
treatment beam. It allows us to treat the tumour from many
different angles in one circular motion. VMAT treatments are very
quick to deliver, meaning that you should be on the treatment bed
for a shorter length of time. At the BHOC we routinely use VMAT
when treating pelvic areas, lungs, chests, brains and head and neck
cancers.
SABR
Stereotactic Ablative Body Radiotherapy (SABR) has been used as
a specialist treatment technique in Bristol since November 2013.
SABR treatments are typically delivered using the same VMAT
delivery technique mentioned above. SABR delivers a very high dose
to a very small tumour volume. Due to the high dose delivered in
each treatment, IGRT plays a vital role in this technique. Cone
beam CT scans will be taken by the treatment machine and assessed
before and during each treatment to ensure you are in the correct
position to accurately deliver your treatment.
SABR can be used to treat different areas of the body including
lungs, liver, lymph nodes, spine and small areas of bone. Each case
is considered on an individual basis as the criteria for SABR is
very restrictive. Your consultant will discuss with you if you are
having SABR treatment.
Clarity
Clarity is the use of live imaging of the treatment area and
other anatomy using an Ultrasound scanner for some prostate
treatments. Clarity monitors the intra-fractional motion (movement
inside the body that cannot be controlled) of the prostate and
surrounding organs. The Clarity system enable us to precisely
manage intra-fraction motion during the treatment beams, providing
gold standard prostate treatment.
With Clarity, we can see and monitor soft-tissue anatomy i.e.
the prostate-without needing extra imaging such as cone beam CT
scans or surgically inserted markers. The benefits of clarity
include providing better visualisation of the prostate, it is a
non-invasive technique, it can be used alongside our already
existing IGRT protocols and once set up carries out automatic
scanning throughout each treatment.
ABC
Active Breathing Coordinator (ABC) provides the non-invasive
immobilisation of certain internal anatomy which is affected by
respiratory motion (breathing), such as the lungs, liver or
pancreas. This is achieved through a simple and efficient assisted
breath-hold technique. ABC is used alongside VMAT and IGRT to
enables us to deliver your treatment to the area with confidence
and accuracy. The benefits of ABC is it immobilises the area for
treatment by restricting movement of the diaphragm and temporarily
pauses breathing, it allows for higher dose delivery when using
techniques such as SABR and it reduced the dose to the healthy
tissues therefore minimising side effects.
If you are having ABC as part of your treatment you will attend
the department for a coaching session which allows you to practice
with the equipment under the guidance of a specially trained
radiographer. You will then use the ABC system all the way through
your treatment.
