gamma knife Flashcards
1
Q
stereotactic
A
the 3D localisation of a point in space by a unique set of coordinates that relate to a fixed external reference frame
2
Q
what is stereotactic radiosurgery
A
- DOES NOT involve any surgical procedure.
- Narrow beams of radiation precisely focused on a small target.
- Tends to be single fraction but can have up to 5#’s.
- Normally delivered usingGammaknife™orCyberknife™.
- Can be delivered using a linear accelerator.
3
Q
aims of SRS
A
- Highly conformal radiotherapy - used to achieve an extremely high concentration of absorbed dose to a small spherical target.
- Can only be used for limited tumour volume size < 3.5cm diameter.
- Extremely rapid dose fall-off to normal surrounding tissue = high therapeutic ratio.
4
Q
advantages of SRS
A
- Reduced toxicity to normal tissue.
- More precise treatment.
- Reduction in acute side effects.
- Fewer appointments required.
5
Q
what is gamma knife
A
- Array of Cobalt 60 sources (varies from 201 – 192)
- Aligned using a collimation system
- sources are focused on the target area and sources can be turned on or off to achieve the best dose to the target.
- Sources are evenly distributed over the surface of the hemispherical source core.
- Each beam is directed at a common focal spot at the centre.
- Enables high doses to be delivered to the abnormal tissues whilst sparing the adjacent healthy tissue.