Folie 1

Protective shielding

Collimator channels

Leksell

Coordinate

Frame

Patient

positioning system

Radiation sources

Isocenter/

Target in the brain

Frame-based Stereotactic Radiosurgery

Positioning Accuracy

Accuracy and stability of positioning in radiosurgery:

long –term results of the Gamma Knife system.

Heck B et al

Med Phys 2007 Apr; 34(4): 1487-95

Graf Chromic films

densitometric measurements

X: - 0.014+/- 0.09mm

Y: 0.013+/- 0.09mm

Z: - 0.002+/- 0.06mm

MRI-based target definition

X: 0.06+/-0.09mm

Y: 0.04+/-0.09mm

All measured data were within a

sphere of 0.2mm radius

Target delineation: GTV=PTV