A noninvasive adapter for stereotaxis guided by computed tomography and magnetic resonance imaging, which was originally developed for morphological (tumour biopsy) surgery, has also been used for functional stereotaxis (thalamotomy, cingulotomy, hypothalamotomy, dentatotomy, etc.), for stereotactic angiography and for external stereotactic irradiation of brain tumours with a conventional linear accelerator. In addition, it has been applied to the location of subcortical brain tumours for open surgery. Recently, the stereoadapter has been supplied with a phantom base, which permits percutaneous tumour biopsy and ventriculostomy without a stereotactic frame.