3. Gamma knife today the first Gamma Knife in 1968
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4. Gamma knife statistics
• 120 gamma knife worldwide
• Over 20000 patients treated annually
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5. introduction
• Gamma Knife radiosurgery, also called
stereotactic radiosurgery.
• Even though it is called surgery; a Gamma
Knife procedure does not involve actual
surgery, nor is the Gamma Knife really a knife
at all.
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6. Technical overview
• There are five current versions of the Leksell
Gamma Knife :
• U
• B
• C
• 4C
• perfexion
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7. • . Each system consists of six components:
• the radiation unit
• the beam-focusing technology
• the patient couch
• an electric bed system
• the control console
• the planning computer system.
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9. prefextion
Figure : Diagrams of the
PERFEXION Gamma Knife
radiation unit and collimator
system. A) Cross section of the
Leksell Gamma Knife
PERFEXION radiation unit. B)
Each sector holds 24 60Co
sources and can be moved
independently on other
sectors to the desired position
to define collimator size or
block groups of beams. C)
Sector position in 4 mm
collimator. D) Sector position
in 8 mm collimator. E) Sector
position in 16 mm collimator.
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10. • 201 cobalt gamma ray beam
sources are arrayed in a
hemisphere and aimed
through a collimator to a
common focal point.
• The patient’s head is
positioned within the
Gamma Knife so that the
tumor is in the focal point of
the gamma rays.
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16. The Leksell Gamma Knife Perfexion offers a non-
invasive, two to four hour procedure that often
allows the patient to leave the center the same
day.
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17. What disorders can the Gamma
Knife treat?
• Malignant tumors
• Arteriovenous malformations (AVM)
• Acoustic Neuroma
• Parkinson's disease
• Familiar tremor
• Trigeminal neuralgia
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19. How is Gamma Knife Surgery
performed?
• Step 1: A stereotactic
head frame is attached
to the head with local
anesthesia
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20. • Step 2: The head is
imaged using a MRI or
CT scanner while the
patient wears the
stereotactic frame.
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21. Step 3: A treatment plan is developed
using the images. Key point: very accurate
delivery possible.
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22. Step 4: The patient lies on the treatment table of
the Gamma Knife while the frame is affixed to the
appropriate collimator.
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23. STEP 5: THE DOOR TO THE TREATMENT UNIT OPENS. THE PATIENT IS
ADVANCED INTO THE SHIELDED TREATMENT VAULT. THE AREA WHERE
ALL OF THE BEAMS INTERSECT IS TREATED WITH A HIGH DOSE OF
RADIATION.
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26. Treatment Planning
• Through an iterative approach we determine:
–the number of shots
–the shot sizes
–the shot locations
–the shot weights
• The quality of the plan is dependent upon the
patience and experience of the user
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33. What are the risks?
• Swelling of the brain
• Headache
• Nausea
• Numbness
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34. …The risks
• Hair loss near treated area (generally
temporary)
• Seizures
• Weakness
• Loss of balance
• Vision problems
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