Post on 15-Jul-2015
FACET - European Journal of Cancer CareMarch 2006
slides available at: www.blackwellpublishing.com/journals/ecc
Stereotactic radiosurgery Gordon, K.1
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What is stereotactic radiosurgery?
• Stereotactic radiosurgery is a non-surgical technique used to selectively destroy abnormalities within the brain.
• Using a machine called the Gamma Knife, 201 sources of Cobalt-60 are focused to a small point (isocentre) ranging from 4-18mm in diameter.
• This tiny area provides a very high dose of radiation which is used to irradiate a focal point within the brain with sub-millimetre accuracy.
FACET - European Journal of Cancer CareMarch 2006
slides available at: www.blackwellpublishing.com/journals/ecc
Stereotactic radiosurgery (continued)S
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History
FACET - European Journal of Cancer CareMarch 2006
slides available at: www.blackwellpublishing.com/journals/ecc
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Stereotactic radiosurgery (continued)
Clinical applications
• Tumours
• Benign
• Malignant
• Functional disorders
• Vascular disorders
FACET - European Journal of Cancer CareMarch 2006
slides available at: www.blackwellpublishing.com/journals/ecc
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Stereotactic radiosurgery (continued)
The procedure
Stereotactic radiosurgery is a four stage procedure:
1. Stereotactic frame fixation
2. Imaging procedures
3. 3D dose planning
4. Gamma Knife treatment.
FACET - European Journal of Cancer CareMarch 2006
slides available at: www.blackwellpublishing.com/journals/ecc
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Stereotactic radiosurgery (continued)
Frame fixation
To immobilise the patient, a frame is fixed to the outer layer of the skull under local anaesthetic using four pins.
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Imaging procedure
All patients will undergo some form of radiographic imaging study with the frame in place in order to localise the area to be treated.
This will either be:
• MRI
• CT
• Angiography
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
3D dose planning
3D dose planning from the radiographic images.
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Gamma Knife treatment
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Side effects• Headaches (most common side
effect)
• Occasional hair loss
• Other symptoms due to raised intracranial pressure and oedema (nausea, vomiting)
• Effects of radiation damage to normal tissues:
• Cranial nerves
• Optic apparatus
• Brain stem
• Necrosis
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Acoustic neuroma
TV at treatment:
6.8cc
TV at 7 months follow-up: 7.4cc
TV at 1yr follow-up:
3.2ccN.B. cc = cubic centimetres
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Single melanoma metastasis
TV at treatment: 17.0cc TV at 5 month follow-up: 1.0cc
TV at 1year follow-up: 1.0cc
TV at 1yr 3month follow-up: 0.756cc
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Multiple metastases: breast
3D view at treatment10 metastases. Total volume = 13.9 cm3
3D View at 6 month follow-up. Only 3 metastases now visible on triple dose contrast enhanced MRITotal volume = 0.6 cm3
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Summary (1)
• Excellent treatment approach for a number of brain abnormalities
• Non invasive
• Single treatment requiring a short hospital stay
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
Summary (2)
• Very few (if any) side effects
• Limitations – due to the nature of the radiation it is more effective when delivered to small areas. Therefore, there is limited use in large tumours and patients are referred for more conventional treatments.
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
The future
• More research to realise the potential in areas such as Parkinson's disease and epilepsy.
• Publish results of such trials, raising awareness within the medical community therefore opening the treatment up to more patients.
• Open more centres around the world to make the treatment more available.
FACET - European Journal of Cancer CareMarch 2006
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Stereotactic radiosurgery (continued)
References and further reading
• http://www.gammaknife.co.uk
• http://www.elekta.com
• http://www.irsa.org/radiosurgery.html
• Gordon K, Eddy D. (2006) The efficacy of Stereotactic Radiosurgery in the management of Vestibular Schwannomas - a retrospective analysis. Journal of Radiotherapy in Practice. 5 (1): 1-12.
• Hickey, K. (2004) Role of stereotactic radiosurgery in the management of single or multiple cerebral metastases. Journal of Radiotherapy in Practice. 3 (4): 197-203.
• Hickey, K. (2004) Conventional and contemporary management approaches for the treatment of vestibular schwannomas: Microsurgery versus radiosurgery, a literature review. Journal of Radiotherapy in Practice. 4 (1): 39-45.