Neuro - Stereotactic Radiosurgery Flashcards
Who create the gamma knife? What is it?
Lars Leksell, it uses the delivery of a single, high dose of irridation of cobalt to a small and critically located intracranial volume through the intact skull. The entire does is sent from multiple directions as to spare good tissue to kill the lesion
How does the gamma knife work?
It sends 201 beams intersecting in one focal point on the target from radioactive cobalt
What are the most effective lesions that can be treated with gamma rays?
Acoustic Neuroma and Metastatis tumors
Also vascular arteriorvenous malformations and even trigeminal neuralgia
What are the steps of gamma knife?
Frame fixation, diagnostic imaging, planning and treatment
What is the importance of frame fixation?
Keeps patient fixated on one point and establishes spatial reference points for accurate delivery to the target. Unfortunately this comes at a price as the frame must be fixed directly to the skull
What types of imaging is used?
MRI is the best unless contraindicated, then CT or is vascular than angiogram
Who is on the the treatment team?
Radiation Oncologist Neurosurgeon Neuroradiologist (for accurate anatomy) Physicist (to maintain cobalt and calculate the amount of time spent in the machine) Nurse (takes care of patient)
What size beam is used?
4,8,14, and 18 mm size shots
How does gamma knife compare to open surgery?
Same day surgery (no time in ICU)
Return to ADL same day (surgery is 5-7 days of hospitalization and 4-6 weeks until fully recovered)
Less risks to bleeds, nerve damage, and ICP increase
What is local control rate and how is it related to gamma knife?
Sterotactic radiosurgery does not remove the lesion from its location. it merely reduces its capacity to replicate. Thus a tumor for example is not considered cured bu rather controlled.
What is the goal of stereotactic radiosurgery in terminally ill patients?
In some cases it is to merely prevent a neurological death
What are the benefits of stereotactic technique?
Less invasive
More precise
Less costly
Less time spent in the hospital
What are the disadvatanges to gamma knife?
Can only treat intracranial targets
Requires an uncomfortable head frame
Not amenable to fractionation
Expensive down costs
What is a cyberknife?
Similar idea to gamma knife but uses focused electron beam
Advantages: can treat entire body
No head frame
can be fractionated
Disadvantages: Limited to radiosurgery
Cost
What is the Trilogy?
Mobile gamma knife
Face mask instead of a head frame
Versatile (rotates around the patient, can do whole body, can be used with veterinarian)
