_tissuePlanes = vtkPlanes::New();
int x1,x2,y1,y2,z1,z2;
this->_imagedata->GetExtent(x1,x2,y1,y2,z1,z2);
_tissuePlanes->SetBounds (x1,x2,y1,y2,z1,z2);
_tissuePlanes = vtkPlanes::New();
int x1,x2,y1,y2,z1,z2;
this->_imagedata->GetExtent(x1,x2,y1,y2,z1,z2);
_tissuePlanes->SetBounds (x1,x2,y1,y2,z1,z2);