An example of a complex shape of an AVM. A – 3D representation of the target volume. AVM has a complicated shape and is located next to the brainstem and encompasses the left optic nerve. B – transverse view of the lower part of the AVM, projection of the isocenter is near the edge of the target volume, radii measured from this point would be significantly different from those measured at the level of the isocenter. C – sagittal view of the AVM at the level of the isocenter. The shape at this level appears to be quite regular. The target volume is adjacent to the brainstem. D – coronal view of the AVM, irregular shape of the AVM is visible better than on the sagittal projection.