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Brain Trauma Radiotherapy
Figure 1: Image of Intracranial Conformal Radiosurgery
the image-guided system means that it is now possible to treat tumours
close to the skull base, such as chordomas and chondoscomas, with
curative intent (see Figure 1 for representation of intracranial conformal
radiosurgery). Previously, with conventional radiation, this was simply not
possible. AVMs also respond well to radiosurgery/radiotherapy.
5
Benefits to the Patient
Clearly, not having to be sedated and screwed into a frame is a good thing
from the patient’s perspective, and there are other benefits too. The ability
to deliver a high dose more precisely than ever before to smaller areas opens
up the range of targets that can be treated and improves confidence of a
successful outcome. This is particularly true for fractionated treatment,
where inaccuracies caused by re-positioning would otherwise have affected
the quality of therapy delivered. Treatment times are also reduced in terms
of both the patient’s requirements and those of the therapy team.
Everything no longer needs to be done in one day: for instance, the mask
fixation and the CT scan can be completed a few days beforehand.
Furthermore, the treatment time in our department is now around 20
The Berlin Experience minutes, which represents a reduction of about 20–30%.
My personal experience encompasses different types of stereotactic
radiosurgery and radiotherapy devices spanning more than 15 years. Until Summary and Conclusion
about 2004, I used conventional equipment with the invasive head frames. Since their introduction in the mid-20th century, radiosurgery and
Since then I have used the BrainLAB/Varian Novalis Tx system in combination radiotherapy have become indispensible tools for treating a range of
with ExacTrac X-ray, coupled with the new image-guided navigation system. tumours, vascular malformations and functional lesions, many of which
An initial evaluation of the Novalis image-guided non-invasive system are inaccessible to other treatment modalities. However, these targets are
conducted at my hospital achieved an accuracy of 1.04±0.47mm, with an often close to or intricately involved with delicate areas of the brain. This
average in-plane deviation of 0.02mm on both the x- and y-axes.
3
means that only the most precise and accurate radiotherapy techniques
can be used. In order to keep the patient still between imaging and
The main advantage of this new system is the treatment we can now offer
for benign brain tumours and functional diseases, for example in the
treatment of trigeminal neuralgia, which is caused by the fifth cranial nerve
The main advantage of this new system
and causes a unique, intense type of pain that quite often has a devastating
effect on the patient. The target is very close to sensitive areas such as the
is the treatment we can now offer for
brainstem and furthermore is very tiny: the diameter of the nerve is less than
benign brain tumours and functional
1–2mm and its volume is about 0.09cm
3
.
4
This requires a high number of
diseases, for example in the treatment
very carefully shaped beams directed to the target in order to spare the
surrounding eloquent tissue. With the new system it is now possible for the of trigeminal neuralgia.
first time to treat trigeminal neuralgia more precisely and reduce the danger
of causing adverse radiation effects. Consequently, in trigeminal neuralgia
patients who do not respond well to conventional interventional surgical starting the procedure, as well as during the procedure, conventional
procedures or drug-based treatments, we have managed to achieve a systems used a stereotactic head frame that was literally screwed into the
success rate of at least 70% in terms of reducing pain or even reaching a patient’s skull. While this was performed under anaesthetic, it was still
pain-free state within four to six weeks. Therefore, for the vast majority of unpleasant for the patient. Moreover, the head frame could not
patients, medication (including its inherent side effects) can be reduced, guarantee perfect immobility and an inherent margin of error needed to
which will considerably improve quality of life with a negligible risk. be added to guarantee the safety of the procedure.
Tumours – both benign and metastatic – can develop in almost any area, Advances in radiosurgery technology now mean that the head frames are
and quite often they are very close to the optic apparatus, brainstem or a thing of the past. Sophisticated imaging techniques, combined with
other sensitive areas of the brain. Previously, with conventional radiosurgery, improved radiation delivery, mean that the position of the target is
it could be very difficult to deliver a really high tumorcidal dose because of known and it can be irradiated successfully. This improves patient
the proximity of the sensitive area. With the image-guided frameless system, comfort, speed of treatment and accuracy, resulting in radiotherapists
it is now possible to deliver much higher doses more accurately. In addition, being able to treat more indications with curative intent. ■
1. Solberg TD, Medin PM, Mullins J, Li S, Quality assurance of radiosurgery field shaping: a comparison with static field 4. Rahimian J, Chen JC, Rao AA, et al., Geometrical accuracy of
immobilization and target localization systems for frameless conformal and noncoplanar circular arcs, Int J Radiat Oncol Biol the Novalis stereotactic radiosurgery system for trigeminal
stereotactic cranial and extracranial hypofractionated Phys, 2001;49(5):1481–91. neuralgia, J Neurosurg, 2004;101(Suppl. 3):351–5.
radiotherapy, Int J Radiat Oncol Biol Phys, 2008;71(1 Suppl.): 3. Wurm RE, Erbel S, Schwenkert I, et al., Novalis frameless 5. Pedroso AG, De Salles AA, Tajik K, et al., Novalis Shaped Beam
S131–5. image-guided noninvasive radiosurgery: initial experience, Radiosurgery of arteriovenous malformations, J Neurosurg,
2. Solberg TD, Boedeker KL, Fogg R, et al., Dynamic arc Neurosurgery, 2008;62(5 Suppl.):A11–17, discussion A17–18. 2004;101(Suppl. 3):425–34.
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